PDF viewer tests: Use const/let instead of var.

CL produced with ESLint --fix and clang-format. This is in preparation for turning on no-var and prefer-const ESLint checks for that folder. Bug: 720034 Change-Id: I6467d1308118f67f076708612247852568fba2bc Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1885652 Commit-Queue: Rebekah Potter <rbpotter@chromium.org> Auto-Submit: Demetrios Papadopoulos <dpapad@chromium.org> Reviewed-by: Rebekah Potter <rbpotter@chromium.org> Cr-Commit-Position: refs/heads/master@{#710439}

PDF viewer tests: Use const/let instead of var.
CL produced with ESLint --fix and clang-format. This is in preparation for turning on no-var and prefer-const ESLint checks for that folder. Bug: 720034 Change-Id: I6467d1308118f67f076708612247852568fba2bc Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1885652 Commit-Queue: Rebekah Potter <rbpotter@chromium.org> Auto-Submit: Demetrios Papadopoulos <dpapad@chromium.org> Reviewed-by: Rebekah Potter <rbpotter@chromium.org> Cr-Commit-Position: refs/heads/master@{#710439}
a5aa5e1c · dpapad · Commit Bot · 75651994 · a5aa5e1c · a5aa5e1c
Commit a5aa5e1c authored Oct 29, 2019 by dpapad Committed by Commit Bot Oct 29, 2019
19 changed files
--- a/chrome/test/data/pdf/basic_plugin_test.js
+++ b/chrome/test/data/pdf/basic_plugin_test.js
@@ -5,7 +5,7 @@
 /**
 * These tests require that the PDF plugin be available to run correctly.
 */
-var tests = [
+const tests = [
  /**
   * Test that the page is sized to the size of the document.
   */
@@ -14,7 +14,7 @@ var tests = [
    chrome.test.assertTrue(viewer.viewport.getZoom() <= 1);
    viewer.viewport.setZoom(1);
-    var sizer = document.getElementById('sizer');
+    const sizer = document.getElementById('sizer');
    chrome.test.assertEq(826, sizer.offsetWidth);
    chrome.test.assertEq(
        1066 + viewer.viewport.topToolbarHeight_, sizer.offsetHeight);
@@ -22,7 +22,7 @@ var tests = [
  },
  function testGetSelectedText() {
-    var client = new PDFScriptingAPI(window, window);
+    const client = new PDFScriptingAPI(window, window);
    client.selectAll();
    client.getSelectedText(chrome.test.callbackPass(function(selectedText) {
      chrome.test.assertEq('this is some text\nsome more text', selectedText);
@@ -48,7 +48,7 @@ var tests = [
      chrome.test.assertEq(27, e.keyCode);
      chrome.test.assertEq('Escape', e.code);
    }));
-    var e = document.createEvent('Event');
+    const e = document.createEvent('Event');
    e.initEvent('keydown');
    e.keyCode = 27;
    e.code = 'Escape';
@@ -56,7 +56,7 @@ var tests = [
  }
 ];
-var scriptingAPI = new PDFScriptingAPI(window, window);
+const scriptingAPI = new PDFScriptingAPI(window, window);
 scriptingAPI.setLoadCallback(function() {
  chrome.test.runTests(tests);
 });
--- a/chrome/test/data/pdf/basic_test.js
+++ b/chrome/test/data/pdf/basic_test.js
@@ -6,20 +6,20 @@ import {getFilenameFromURL, shouldIgnoreKeyEvents} from 'chrome-extension://mhjf
 import {$} from 'chrome://resources/js/util.m.js';
 import {pressAndReleaseKeyOn} from 'chrome://resources/polymer/v3_0/iron-test-helpers/mock-interactions.js';
-var tests = [
+const tests = [
  /**
   * Test that some key elements exist and that they have a shadowRoot. This
   * verifies that Polymer is working correctly.
   */
  function testHasElements() {
-    var elementNames = [
+    const elementNames = [
      'viewer-pdf-toolbar',
      'viewer-zoom-toolbar',
      'viewer-password-screen',
      'viewer-error-screen',
    ];
-    for (var i = 0; i < elementNames.length; i++) {
+    for (let i = 0; i < elementNames.length; i++) {
-      var elements = document.body.querySelectorAll(elementNames[i]);
+      const elements = document.body.querySelectorAll(elementNames[i]);
      chrome.test.assertEq(1, elements.length);
      chrome.test.assertTrue(elements[0].shadowRoot !== null);
    }
@@ -30,7 +30,7 @@ var tests = [
   * Test that the plugin element exists and is navigated to the correct URL.
   */
  function testPluginElement() {
-    var plugin = document.getElementById('plugin');
+    const plugin = document.getElementById('plugin');
    chrome.test.assertEq('embed', plugin.localName);
    chrome.test.assertTrue(
@@ -44,7 +44,7 @@ var tests = [
   */
  function testIgnoreKeyEvents() {
    // Test that the traversal through the shadow DOM works correctly.
-    var toolbar = document.getElementById('toolbar');
+    const toolbar = document.getElementById('toolbar');
    toolbar.$.pageselector.pageSelector.inputElement.focus();
    chrome.test.assertTrue(shouldIgnoreKeyEvents(toolbar));
@@ -63,11 +63,11 @@ var tests = [
   * pressing escape.
   */
  function testOpenCloseBookmarks() {
-    var toolbar = $('toolbar');
+    const toolbar = $('toolbar');
    toolbar.show();
-    var dropdown = toolbar.$.bookmarks;
+    const dropdown = toolbar.$.bookmarks;
-    var plugin = $('plugin');
+    const plugin = $('plugin');
-    var ESC_KEY = 27;
+    const ESC_KEY = 27;
    // Clicking on the plugin should close the bookmarks menu.
    chrome.test.assertFalse(dropdown.dropdownOpen);

--- a/chrome/test/data/pdf/beep_test.js
+++ b/chrome/test/data/pdf/beep_test.js
@@ -2,7 +2,7 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
-var tests = [
+const tests = [
  /**
   * Test that the JS was able to call back via "app.beep()"
   */
@@ -12,7 +12,7 @@ var tests = [
  }
 ];
-var scriptingAPI = new PDFScriptingAPI(window, window);
+const scriptingAPI = new PDFScriptingAPI(window, window);
 scriptingAPI.setLoadCallback(function() {
  chrome.test.runTests(tests);
 });
--- a/chrome/test/data/pdf/bookmarks_test.js
+++ b/chrome/test/data/pdf/bookmarks_test.js
@@ -5,22 +5,22 @@
 import {flush} from 'chrome://resources/polymer/v3_0/polymer/polymer_bundled.min.js';
 import {createBookmarksForTest} from './test_util.js';
-var tests = [
+const tests = [
  /**
   * Test that the correct bookmarks were loaded for
   * test-bookmarks-with-zoom.pdf.
   */
  function testHasCorrectBookmarks() {
-    var bookmarks = viewer.bookmarks;
+    const bookmarks = viewer.bookmarks;
    // Load all relevant bookmarks.
    chrome.test.assertEq(3, bookmarks.length);
-    var firstBookmark = bookmarks[0];
+    const firstBookmark = bookmarks[0];
-    var secondBookmark = bookmarks[1];
+    const secondBookmark = bookmarks[1];
-    var uriBookmark = bookmarks[2];
+    const uriBookmark = bookmarks[2];
    chrome.test.assertEq(1, firstBookmark.children.length);
    chrome.test.assertEq(0, secondBookmark.children.length);
-    var firstNestedBookmark = firstBookmark.children[0];
+    const firstNestedBookmark = firstBookmark.children[0];
    // Check titles.
    chrome.test.assertEq('First Section', firstBookmark.title);
@@ -60,28 +60,28 @@ var tests = [
   * test-bookmarks-with-zoom.pdf.
   */
  function testFollowBookmark() {
-    var bookmarkContent = createBookmarksForTest();
+    const bookmarkContent = createBookmarksForTest();
    bookmarkContent.bookmarks = viewer.bookmarks;
    document.body.appendChild(bookmarkContent);
    flush();
-    var rootBookmarks =
+    const rootBookmarks =
        bookmarkContent.shadowRoot.querySelectorAll('viewer-bookmark');
    chrome.test.assertEq(3, rootBookmarks.length, 'three root bookmarks');
    rootBookmarks[0].$.expand.click();
    flush();
-    var subBookmarks =
+    const subBookmarks =
        rootBookmarks[0].shadowRoot.querySelectorAll('viewer-bookmark');
    chrome.test.assertEq(1, subBookmarks.length, 'one sub bookmark');
-    var lastPageChange;
+    let lastPageChange;
-    var lastXChange;
+    let lastXChange;
-    var lastYChange;
+    let lastYChange;
-    var lastZoomChange;
+    let lastZoomChange;
-    var lastUriNavigation;
+    let lastUriNavigation;
    bookmarkContent.addEventListener('change-page', function(e) {
      lastPageChange = e.detail.page;
      lastXChange = undefined;
@@ -129,7 +129,7 @@ var tests = [
  }
 ];
-var scriptingAPI = new PDFScriptingAPI(window, window);
+const scriptingAPI = new PDFScriptingAPI(window, window);
 scriptingAPI.setLoadCallback(function() {
  chrome.test.runTests(tests);
 });
--- a/chrome/test/data/pdf/gesture_detector_test.js
+++ b/chrome/test/data/pdf/gesture_detector_test.js
@@ -25,7 +25,7 @@ chrome.test.runTests(function() {
    }
    sendEvent(event) {
-      for (let l of this.listeners.get(event.type)) {
+      for (const l of this.listeners.get(event.type)) {
        l.listener(event);
      }
    }
@@ -73,9 +73,9 @@ chrome.test.runTests(function() {
  return [
    function testPinchZoomIn() {
-      let stubElement = new StubElement();
+      const stubElement = new StubElement();
-      let gestureDetector = new GestureDetector(stubElement);
+      const gestureDetector = new GestureDetector(stubElement);
-      let pinchListener = new PinchListener(gestureDetector);
+      const pinchListener = new PinchListener(gestureDetector);
      stubElement.sendEvent(new MockTouchEvent('touchstart', [
        {clientX: 0, clientY: 0},
@@ -121,9 +121,9 @@ chrome.test.runTests(function() {
    },
    function testPinchZoomInAndBackOut() {
-      let stubElement = new StubElement();
+      const stubElement = new StubElement();
-      let gestureDetector = new GestureDetector(stubElement);
+      const gestureDetector = new GestureDetector(stubElement);
-      let pinchListener = new PinchListener(gestureDetector);
+      const pinchListener = new PinchListener(gestureDetector);
      stubElement.sendEvent(new MockTouchEvent('touchstart', [
        {clientX: 0, clientY: 0},
@@ -171,9 +171,9 @@ chrome.test.runTests(function() {
    },
    function testZoomWithWheel() {
-      let stubElement = new StubElement();
+      const stubElement = new StubElement();
-      let gestureDetector = new GestureDetector(stubElement);
+      const gestureDetector = new GestureDetector(stubElement);
-      let pinchListener = new PinchListener(gestureDetector);
+      const pinchListener = new PinchListener(gestureDetector);
      // Since the wheel events that the GestureDetector receives are
      // individual updates without begin/end events, we need to make sure the
@@ -189,16 +189,16 @@ chrome.test.runTests(function() {
          });
        }
      }
-      let pinchSequenceListener = new PinchSequenceListener(gestureDetector);
+      const pinchSequenceListener = new PinchSequenceListener(gestureDetector);
-      let scale = 1.23;
+      const scale = 1.23;
-      let deltaY = -(100.0 * Math.log(scale));
+      const deltaY = -(100.0 * Math.log(scale));
-      let position = {clientX: 12, clientY: 34};
+      const position = {clientX: 12, clientY: 34};
      stubElement.sendEvent(new MockWheelEvent(deltaY, position, true));
      chrome.test.assertTrue(pinchSequenceListener.seenBegin);
-      let lastEvent = pinchListener.lastEvent;
+      const lastEvent = pinchListener.lastEvent;
      chrome.test.assertEq('pinchupdate', lastEvent.type);
      chrome.test.assertTrue(Math.abs(lastEvent.scaleRatio - scale) < 0.001);
      chrome.test.assertEq('in', lastEvent.direction);
@@ -211,11 +211,11 @@ chrome.test.runTests(function() {
    },
    function testIgnoreTouchScrolling() {
-      let stubElement = new StubElement();
+      const stubElement = new StubElement();
-      let gestureDetector = new GestureDetector(stubElement);
+      const gestureDetector = new GestureDetector(stubElement);
-      let pinchListener = new PinchListener(gestureDetector);
+      const pinchListener = new PinchListener(gestureDetector);
-      let touchScrollStartEvent = new MockTouchEvent('touchstart', [
+      const touchScrollStartEvent = new MockTouchEvent('touchstart', [
        {clientX: 0, clientY: 0},
      ]);
      stubElement.sendEvent(touchScrollStartEvent);
@@ -234,12 +234,12 @@ chrome.test.runTests(function() {
    },
    function testIgnoreWheelScrolling() {
-      let stubElement = new StubElement();
+      const stubElement = new StubElement();
-      let gestureDetector = new GestureDetector(stubElement);
+      const gestureDetector = new GestureDetector(stubElement);
-      let pinchListener = new PinchListener(gestureDetector);
+      const pinchListener = new PinchListener(gestureDetector);
      // A wheel event where ctrlKey is false does not indicate zooming.
-      let scrollingWheelEvent =
+      const scrollingWheelEvent =
          new MockWheelEvent(1, {clientX: 0, clientY: 0}, false);
      stubElement.sendEvent(scrollingWheelEvent);
      chrome.test.assertEq(null, pinchListener.lastEvent);
@@ -248,7 +248,7 @@ chrome.test.runTests(function() {
    },
    function testPreventNativePinchZoom() {
-      let touchAction =
+      const touchAction =
          window.getComputedStyle(document.documentElement).touchAction;
      chrome.test.assertEq('pan-x pan-y', touchAction);
@@ -257,15 +257,15 @@ chrome.test.runTests(function() {
    },
    function testPreventNativeZoomFromWheel() {
-      let stubElement = new StubElement();
+      const stubElement = new StubElement();
-      let gestureDetector = new GestureDetector(stubElement);
+      const gestureDetector = new GestureDetector(stubElement);
-      let pinchListener = new PinchListener(gestureDetector);
+      const pinchListener = new PinchListener(gestureDetector);
      // Ensure that the wheel listener is not passive, otherwise the call to
      // preventDefault will be ignored. Since listeners could default to being
      // passive, we must set the value explicitly.
-      for (let l of stubElement.listeners.get('wheel')) {
+      for (const l of stubElement.listeners.get('wheel')) {
-        let options = l.options;
+        const options = l.options;
        chrome.test.assertTrue(
            !!options && typeof (options.passive) == 'boolean');
        chrome.test.assertFalse(options.passive);
@@ -273,12 +273,12 @@ chrome.test.runTests(function() {
      // We should not preventDefault a wheel event where ctrlKey is false as
      // that would prevent scrolling, not zooming.
-      let scrollingWheelEvent =
+      const scrollingWheelEvent =
          new MockWheelEvent(1, {clientX: 0, clientY: 0}, false);
      stubElement.sendEvent(scrollingWheelEvent);
      chrome.test.assertFalse(scrollingWheelEvent.defaultPrevented);
-      let zoomingWheelEvent =
+      const zoomingWheelEvent =
          new MockWheelEvent(1, {clientX: 0, clientY: 0}, true);
      stubElement.sendEvent(zoomingWheelEvent);
      chrome.test.assertTrue(zoomingWheelEvent.defaultPrevented);
@@ -287,8 +287,8 @@ chrome.test.runTests(function() {
    },
    function testWasTwoFingerTouch() {
-      let stubElement = new StubElement();
+      const stubElement = new StubElement();
-      let gestureDetector = new GestureDetector(stubElement);
+      const gestureDetector = new GestureDetector(stubElement);
      chrome.test.assertFalse(

--- a/chrome/test/data/pdf/material_elements_test.js
+++ b/chrome/test/data/pdf/material_elements_test.js
@@ -33,25 +33,25 @@ class FitToEventChecker {
 /**
 * Standalone unit tests of the PDF Polymer elements.
 */
-var tests = [
+const tests = [
  /**
   * Test that viewer-page-selector reacts correctly to text entry. The page
   * selector validates that input is an integer, and does not allow navigation
   * past document bounds.
   */
  function testPageSelectorChange() {
-    var selector = document.createElement('viewer-page-selector');
+    const selector = document.createElement('viewer-page-selector');
    selector.docLength = 1234;
    document.body.appendChild(selector);
-    var input = selector.pageSelector;
+    const input = selector.pageSelector;
    // Simulate entering text into `input` and pressing enter.
    function changeInput(newValue) {
      input.value = newValue;
      input.dispatchEvent(new CustomEvent('change'));
    }
-    var navigatedPages = [];
+    const navigatedPages = [];
    selector.addEventListener('change-page', function(e) {
      navigatedPages.push(e.detail.page);
      // A change-page handler is expected to set the pageNo to the new value.
@@ -80,7 +80,7 @@ var tests = [
   * Test that viewer-page-selector changes in response to setting docLength.
   */
  function testPageSelectorDocLength() {
-    var selector = document.createElement('viewer-page-selector');
+    const selector = document.createElement('viewer-page-selector');
    selector.docLength = 1234;
    document.body.appendChild(selector);
    chrome.test.assertEq('1234', selector.$.pagelength.textContent);
@@ -93,7 +93,7 @@ var tests = [
   * Test that clicking the dropdown icon opens/closes the dropdown.
   */
  function testToolbarDropdownShowHide() {
-    var dropdown = document.createElement('viewer-toolbar-dropdown');
+    const dropdown = document.createElement('viewer-toolbar-dropdown');
    dropdown.header = 'Test Menu';
    dropdown.closedIcon = 'closedIcon';
    dropdown.openIcon = 'openIcon';
@@ -120,7 +120,7 @@ var tests = [
   * structure and behaviour.
   */
  function testBookmarkStructure() {
-    var bookmarkContent = createBookmarksForTest();
+    const bookmarkContent = createBookmarksForTest();
    bookmarkContent.bookmarks = [{
      title: 'Test 1',
      page: 1,
@@ -134,21 +134,21 @@ var tests = [
    // Force templates to render.
    flush();
-    var rootBookmarks =
+    const rootBookmarks =
        bookmarkContent.shadowRoot.querySelectorAll('viewer-bookmark');
    chrome.test.assertEq(1, rootBookmarks.length, 'one root bookmark');
-    var rootBookmark = rootBookmarks[0];
+    const rootBookmark = rootBookmarks[0];
    rootBookmark.$.expand.click();
    flush();
-    var subBookmarks =
+    const subBookmarks =
        rootBookmark.shadowRoot.querySelectorAll('viewer-bookmark');
    chrome.test.assertEq(2, subBookmarks.length, 'two sub bookmarks');
    chrome.test.assertEq(
        1, subBookmarks[1].depth, 'sub bookmark depth correct');
-    var lastPageChange;
+    let lastPageChange;
    rootBookmark.addEventListener('change-page', function(e) {
      lastPageChange = e.detail.page;
    });
@@ -167,15 +167,15 @@ var tests = [
   * fit-to-width buttons.
   */
  function testZoomToolbarToggle() {
-    var zoomToolbar = document.createElement('viewer-zoom-toolbar');
+    const zoomToolbar = document.createElement('viewer-zoom-toolbar');
    document.body.appendChild(zoomToolbar);
-    var fitButton = zoomToolbar.$['fit-button'];
+    const fitButton = zoomToolbar.$['fit-button'];
-    var button = fitButton.$$('cr-icon-button');
+    const button = fitButton.$$('cr-icon-button');
-    var fitWidthIcon = 'fullscreen';
+    const fitWidthIcon = 'fullscreen';
-    var fitPageIcon = 'fullscreen-exit';
+    const fitPageIcon = 'fullscreen-exit';
-    var fitToEventChecker = new FitToEventChecker(zoomToolbar);
+    const fitToEventChecker = new FitToEventChecker(zoomToolbar);
    // Initial: Show fit-to-page.
    // TODO(tsergeant): This assertion attempts to be resilient to iconset
@@ -218,15 +218,15 @@ var tests = [
  },
  function testZoomToolbarForceFitToPage() {
-    var zoomToolbar = document.createElement('viewer-zoom-toolbar');
+    const zoomToolbar = document.createElement('viewer-zoom-toolbar');
    document.body.appendChild(zoomToolbar);
-    var fitButton = zoomToolbar.$['fit-button'];
+    const fitButton = zoomToolbar.$['fit-button'];
-    var button = fitButton.$$('cr-icon-button');
+    const button = fitButton.$$('cr-icon-button');
-    var fitWidthIcon = 'fullscreen';
+    const fitWidthIcon = 'fullscreen';
-    var fitPageIcon = 'fullscreen-exit';
+    const fitPageIcon = 'fullscreen-exit';
-    var fitToEventChecker = new FitToEventChecker(zoomToolbar);
+    const fitToEventChecker = new FitToEventChecker(zoomToolbar);
    // Initial: Show fit-to-page.
    chrome.test.assertTrue(button.ironIcon.endsWith(fitPageIcon));
@@ -260,15 +260,15 @@ var tests = [
  },
  function testZoomToolbarForceFitToWidth() {
-    var zoomToolbar = document.createElement('viewer-zoom-toolbar');
+    const zoomToolbar = document.createElement('viewer-zoom-toolbar');
    document.body.appendChild(zoomToolbar);
-    var fitButton = zoomToolbar.$['fit-button'];
+    const fitButton = zoomToolbar.$['fit-button'];
-    var button = fitButton.$$('cr-icon-button');
+    const button = fitButton.$$('cr-icon-button');
-    var fitWidthIcon = 'fullscreen';
+    const fitWidthIcon = 'fullscreen';
-    var fitPageIcon = 'fullscreen-exit';
+    const fitPageIcon = 'fullscreen-exit';
-    var fitToEventChecker = new FitToEventChecker(zoomToolbar);
+    const fitToEventChecker = new FitToEventChecker(zoomToolbar);
    // Initial: Show fit-to-page.
    chrome.test.assertTrue(button.ironIcon.endsWith(fitPageIcon));

--- a/chrome/test/data/pdf/metrics_test.js
+++ b/chrome/test/data/pdf/metrics_test.js
@@ -44,7 +44,7 @@ chrome.test.runTests(function() {
      chrome.metricsPrivate = new MockMetricsPrivate();
      PDFMetrics.record(PDFMetrics.UserAction.DOCUMENT_OPENED);
-      for (var i = 0; i < 4; i++) {
+      for (let i = 0; i < 4; i++) {
        PDFMetrics.record(PDFMetrics.UserAction.ROTATE);
      }

--- a/chrome/test/data/pdf/navigator_test.js
+++ b/chrome/test/data/pdf/navigator_test.js
@@ -78,18 +78,18 @@ function doNavigationUrlTest(
 * tab, and a new window.
 */
 function doNavigationUrlTests(originalUrl, url, expectedResultUrl) {
-  var mockWindow = new MockWindow(100, 100);
+  const mockWindow = new MockWindow(100, 100);
-  var mockSizer = new MockSizer();
+  const mockSizer = new MockSizer();
-  var mockViewportChangedCallback = new MockViewportChangedCallback();
+  const mockViewportChangedCallback = new MockViewportChangedCallback();
-  var viewport = new Viewport(mockWindow, mockSizer, 0, 1, 0);
+  const viewport = new Viewport(mockWindow, mockSizer, 0, 1, 0);
  viewport.setViewportChangedCallback(mockViewportChangedCallback.callback);
-  var paramsParser = new OpenPdfParamsParser(function(name) {
+  const paramsParser = new OpenPdfParamsParser(function(name) {
    paramsParser.onNamedDestinationReceived(-1);
  });
-  var navigatorDelegate = new MockNavigatorDelegate();
+  const navigatorDelegate = new MockNavigatorDelegate();
-  var navigator =
+  const navigator =
      new PdfNavigator(originalUrl, viewport, paramsParser, navigatorDelegate);
  doNavigationUrlTest(
@@ -103,19 +103,19 @@ function doNavigationUrlTests(originalUrl, url, expectedResultUrl) {
      expectedResultUrl, mockViewportChangedCallback, navigatorDelegate);
 }
-var tests = [
+const tests = [
  /**
   * Test navigation within the page, opening a url in the same tab and
   * opening a url in a new tab.
   */
  function testNavigate() {
-    var mockWindow = new MockWindow(100, 100);
+    const mockWindow = new MockWindow(100, 100);
-    var mockSizer = new MockSizer();
+    const mockSizer = new MockSizer();
-    var mockCallback = new MockViewportChangedCallback();
+    const mockCallback = new MockViewportChangedCallback();
-    var viewport = new Viewport(mockWindow, mockSizer, 0, 1, 0);
+    const viewport = new Viewport(mockWindow, mockSizer, 0, 1, 0);
    viewport.setViewportChangedCallback(mockCallback.callback);
-    var paramsParser = new OpenPdfParamsParser(function(destination) {
+    const paramsParser = new OpenPdfParamsParser(function(destination) {
      if (destination == 'US') {
        paramsParser.onNamedDestinationReceived(0);
      } else if (destination == 'UY') {
@@ -124,13 +124,13 @@ var tests = [
        paramsParser.onNamedDestinationReceived(-1);
      }
    });
-    var url = 'http://xyz.pdf';
+    const url = 'http://xyz.pdf';
-    var navigatorDelegate = new MockNavigatorDelegate();
+    const navigatorDelegate = new MockNavigatorDelegate();
-    var navigator =
+    const navigator =
        new PdfNavigator(url, viewport, paramsParser, navigatorDelegate);
-    var documentDimensions = new MockDocumentDimensions();
+    const documentDimensions = new MockDocumentDimensions();
    documentDimensions.addPage(100, 100);
    documentDimensions.addPage(200, 200);
    documentDimensions.addPage(100, 400);
@@ -185,7 +185,7 @@ var tests = [
   * similar heuristics as Adobe Acrobat Reader.
   */
  function testNavigateForLinksWithoutScheme() {
-    var url = 'http://www.example.com/subdir/xyz.pdf';
+    const url = 'http://www.example.com/subdir/xyz.pdf';
    // Sanity check.
    doNavigationUrlTests(
@@ -232,7 +232,7 @@ var tests = [
   * a file:/// url as the current location.
   */
  function testNavigateFromLocalFile() {
-    var url = 'file:///some/path/to/myfile.pdf';
+    const url = 'file:///some/path/to/myfile.pdf';
    // Open an absolute link.
    doNavigationUrlTests(
@@ -242,7 +242,7 @@ var tests = [
  },
  function testNavigateInvalidUrls() {
-    var url = 'https://example.com/some-web-document.pdf';
+    const url = 'https://example.com/some-web-document.pdf';
    // From non-file: to file:
    doNavigationUrlTests(url, 'file:///bar.pdf', undefined);
@@ -261,7 +261,7 @@ var tests = [
  }
 ];
-var scriptingAPI = new PDFScriptingAPI(window, window);
+const scriptingAPI = new PDFScriptingAPI(window, window);
 scriptingAPI.setLoadCallback(function() {
  chrome.test.runTests(tests);
 });
--- a/chrome/test/data/pdf/nobeep_test.js
+++ b/chrome/test/data/pdf/nobeep_test.js
@@ -2,7 +2,7 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
-var tests = [
+const tests = [
  /**
   * Test that blocked JS was not able to call back via "app.beep()"
   */
@@ -12,7 +12,7 @@ var tests = [
  }
 ];
-var scriptingAPI = new PDFScriptingAPI(window, window);
+const scriptingAPI = new PDFScriptingAPI(window, window);
 scriptingAPI.setLoadCallback(function() {
  chrome.test.runTests(tests);
 });
--- a/chrome/test/data/pdf/page_change_test.js
+++ b/chrome/test/data/pdf/page_change_test.js
@@ -14,7 +14,7 @@ function getCurrentPage() {
  return window.viewer.viewport.getMostVisiblePage();
 }
-var tests = [
+const tests = [
  /**
   * Test that the left/right arrows change page back and forth.
   */

--- a/chrome/test/data/pdf/params_parser_test.js
+++ b/chrome/test/data/pdf/params_parser_test.js
@@ -5,12 +5,12 @@
 import {OpenPdfParamsParser} from 'chrome-extension://mhjfbmdgcfjbbpaeojofohoefgiehjai/open_pdf_params_parser.js';
 import {FittingType} from 'chrome-extension://mhjfbmdgcfjbbpaeojofohoefgiehjai/pdf_fitting_type.js';
-var tests = [
+const tests = [
  /**
   * Test named destinations.
   */
  function testParamsParser() {
-    var paramsParser = new OpenPdfParamsParser(function(destination) {
+    const paramsParser = new OpenPdfParamsParser(function(destination) {
      if (destination == 'RU') {
        paramsParser.onNamedDestinationReceived(26);
      } else if (destination == 'US') {
@@ -22,7 +22,7 @@ var tests = [
      }
    });
-    var url = 'http://xyz.pdf';
+    const url = 'http://xyz.pdf';
    // Checking #nameddest.
    paramsParser.getViewportFromUrlParams(`${url}#RU`, function(params) {
@@ -138,7 +138,7 @@ var tests = [
        });
    // Checking #toolbar=0 to disable the toolbar.
-    var uiParams = paramsParser.getUiUrlParams(`${url}#toolbar=0`);
+    let uiParams = paramsParser.getUiUrlParams(`${url}#toolbar=0`);
    chrome.test.assertFalse(uiParams.toolbar);
    uiParams = paramsParser.getUiUrlParams(`${url}#toolbar=1`);
    chrome.test.assertTrue(uiParams.toolbar);
@@ -147,7 +147,7 @@ var tests = [
  }
 ];
-var scriptingAPI = new PDFScriptingAPI(window, window);
+const scriptingAPI = new PDFScriptingAPI(window, window);
 scriptingAPI.setLoadCallback(function() {
  chrome.test.runTests(tests);
 });
--- a/chrome/test/data/pdf/redirects_fail_test.js
+++ b/chrome/test/data/pdf/redirects_fail_test.js
@@ -4,7 +4,7 @@
 // Load a plugin with the given paramaters.
 function createPluginForUrl(streamUrl, url, headers, progressCallback) {
-  var plugin = document.createElement('embed');
+  const plugin = document.createElement('embed');
  plugin.type = 'application/x-google-chrome-pdf';
  plugin.addEventListener('message', function(message) {
    switch (message.data.type.toString()) {
@@ -22,16 +22,16 @@ function createPluginForUrl(streamUrl, url, headers, progressCallback) {
 }
 function parseUrl(url) {
-  var a = document.createElement('a');
+  const a = document.createElement('a');
  a.href = url;
  return a;
 }
-var tests = [
+const tests = [
  // Test that if the plugin is loaded with a URL that redirects it fails.
  function redirectsFail() {
-    var url = parseUrl(viewer.originalUrl_);
+    const url = parseUrl(viewer.originalUrl_);
-    var redirectUrl = url.origin + '/server-redirect?' + viewer.originalUrl_;
+    const redirectUrl = url.origin + '/server-redirect?' + viewer.originalUrl_;
    createPluginForUrl(redirectUrl, redirectUrl, '', function(progress) {
      if (progress == -1) {
        chrome.test.succeed();
@@ -44,12 +44,12 @@ var tests = [
  // Test that if the plugin is loaded with a URL that doesn't redirect but
  // subsequent requests do redirect, it fails.
  function partialRedirectsFail() {
-    var url = parseUrl(viewer.originalUrl_);
+    const url = parseUrl(viewer.originalUrl_);
-    var redirectUrl = url.origin + '/server-redirect?' + viewer.originalUrl_;
+    const redirectUrl = url.origin + '/server-redirect?' + viewer.originalUrl_;
    // Set the headers manually so that the first request is made using a URL
    // that doesn't redirect and subsequent requests are made using a URL that
    // does.
-    var headers = 'Accept-Ranges: bytes\n' +
+    const headers = 'Accept-Ranges: bytes\n' +
        'Content-Length: 101688487\n' +
        'Content-Type: application/pdf\n';
    createPluginForUrl(
@@ -74,7 +74,7 @@ var tests = [
  },
 ];
-var scriptingAPI = new PDFScriptingAPI(window, window);
+const scriptingAPI = new PDFScriptingAPI(window, window);
 scriptingAPI.setLoadCallback(function() {
  chrome.test.runTests(tests);
 });
--- a/chrome/test/data/pdf/test_util.js
+++ b/chrome/test/data/pdf/test_util.js
@@ -56,7 +56,7 @@ export function MockWindow(width, height, sizer) {
 }
 export function MockSizer() {
-  var sizer = this;
+  const sizer = this;
  this.style = {
    width_: '0px',
    height_: '0px',
@@ -97,7 +97,7 @@ export function MockDocumentDimensions(width, height, layoutOptions) {
  this.layoutOptions = layoutOptions;
  this.pageDimensions = [];
  this.addPage = function(w, h) {
-    var y = 0;
+    let y = 0;
    if (this.pageDimensions.length != 0) {
      y = this.pageDimensions[this.pageDimensions.length - 1].y +
          this.pageDimensions[this.pageDimensions.length - 1].height;

--- a/chrome/test/data/pdf/title_test.js
+++ b/chrome/test/data/pdf/title_test.js
@@ -2,7 +2,7 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
-var tests = [
+const tests = [
  /**
   * Test that the correct title is displayed for test-title.pdf.
   */
@@ -13,7 +13,7 @@ var tests = [
  }
 ];
-var scriptingAPI = new PDFScriptingAPI(window, window);
+const scriptingAPI = new PDFScriptingAPI(window, window);
 scriptingAPI.setLoadCallback(function() {
  chrome.test.runTests(tests);
 });
--- a/chrome/test/data/pdf/toolbar_manager_test.js
+++ b/chrome/test/data/pdf/toolbar_manager_test.js
@@ -9,13 +9,13 @@ import {MockWindow} from './test_util.js';
 // A cut-down version of MockInteractions.move, which is not exposed
 // publicly.
 function getMouseMoveEvents(fromX, fromY, toX, toY, steps) {
-  var dx = Math.round((toX - fromX) / steps);
+  const dx = Math.round((toX - fromX) / steps);
-  var dy = Math.round((toY - fromY) / steps);
+  const dy = Math.round((toY - fromY) / steps);
-  var events = [];
+  const events = [];
  // Deliberate <= to ensure that an event is run for toX, toY
-  for (var i = 0; i <= steps; i++) {
+  for (let i = 0; i <= steps; i++) {
-    var e = new MouseEvent('mousemove', {
+    const e = new MouseEvent('mousemove', {
      clientX: fromX,
      clientY: fromY,
      movementX: dx,
@@ -29,7 +29,7 @@ function getMouseMoveEvents(fromX, fromY, toX, toY, steps) {
 }
 function makeTapEvent(x, y) {
-  var e = new MouseEvent('mousemove', {
+  const e = new MouseEvent('mousemove', {
    clientX: x,
    clientY: y,
    movementX: 0,
@@ -48,22 +48,22 @@ function mockGetCurrentTimestamp() {
  return 1449000000000 + this.callCount * 50;
 }
-var tests = [
+const tests = [
  /**
   * Test that ToolbarManager.forceHideTopToolbar hides (or shows) the top
   * toolbar correctly for different mouse movements.
   */
  function testToolbarManagerForceHideTopToolbar() {
-    var mockWindow = new MockWindow(1920, 1080);
+    const mockWindow = new MockWindow(1920, 1080);
-    var toolbar = document.createElement('viewer-pdf-toolbar');
+    const toolbar = document.createElement('viewer-pdf-toolbar');
    document.body.appendChild(toolbar);
-    var zoomToolbar = document.createElement('viewer-zoom-toolbar');
+    const zoomToolbar = document.createElement('viewer-zoom-toolbar');
    document.body.appendChild(zoomToolbar);
-    var toolbarManager = new ToolbarManager(mockWindow, toolbar, zoomToolbar);
+    const toolbarManager = new ToolbarManager(mockWindow, toolbar, zoomToolbar);
    toolbarManager.getCurrentTimestamp_ = mockGetCurrentTimestamp;
-    var mouseMove = function(fromX, fromY, toX, toY, steps) {
+    const mouseMove = function(fromX, fromY, toX, toY, steps) {
      getMouseMoveEvents(fromX, fromY, toX, toY, steps).forEach(function(e) {
        toolbarManager.handleMouseMove(e);
      });
@@ -103,15 +103,15 @@ var tests = [
   * Test that changes to window height bubble down to dropdowns correctly.
   */
  function testToolbarManagerResizeDropdown() {
-    var mockWindow = new MockWindow(1920, 1080);
+    const mockWindow = new MockWindow(1920, 1080);
-    var mockZoomToolbar = {
+    const mockZoomToolbar = {
      clientHeight: 400,
      isPrintPreview: false,
    };
-    var toolbar = document.getElementById('toolbar');
+    const toolbar = document.getElementById('toolbar');
-    var bookmarksDropdown = toolbar.$.bookmarks;
+    const bookmarksDropdown = toolbar.$.bookmarks;
-    var toolbarManager =
+    const toolbarManager =
        new ToolbarManager(mockWindow, toolbar, mockZoomToolbar);
    chrome.test.assertEq(680, bookmarksDropdown.lowerBound);
@@ -126,16 +126,16 @@ var tests = [
   * Test that the toolbar will not be hidden when navigating with the tab key.
   */
  function testToolbarKeyboardNavigation() {
-    var mockWindow = new MockWindow(1920, 1080);
+    const mockWindow = new MockWindow(1920, 1080);
-    var toolbar = document.createElement('viewer-pdf-toolbar');
+    const toolbar = document.createElement('viewer-pdf-toolbar');
    toolbar.loadProgress = 100;
    document.body.appendChild(toolbar);
-    var zoomToolbar = document.createElement('viewer-zoom-toolbar');
+    const zoomToolbar = document.createElement('viewer-zoom-toolbar');
    document.body.appendChild(zoomToolbar);
-    var toolbarManager = new ToolbarManager(mockWindow, toolbar, zoomToolbar);
+    const toolbarManager = new ToolbarManager(mockWindow, toolbar, zoomToolbar);
    toolbarManager.getCurrentTimestamp_ = mockGetCurrentTimestamp;
-    var mouseMove = function(fromX, fromY, toX, toY, steps) {
+    const mouseMove = function(fromX, fromY, toX, toY, steps) {
      getMouseMoveEvents(fromX, fromY, toX, toY, steps).forEach(function(e) {
        toolbarManager.handleMouseMove(e);
      });
@@ -170,12 +170,12 @@ var tests = [
   * Preview.
   */
  function testToolbarManagerResetKeyboardNavigation() {
-    var mockWindow = new MockWindow(1920, 1080);
+    const mockWindow = new MockWindow(1920, 1080);
-    var zoomToolbar = document.createElement('viewer-zoom-toolbar');
+    const zoomToolbar = document.createElement('viewer-zoom-toolbar');
    zoomToolbar.isPrintPreview = true;
    document.body.appendChild(zoomToolbar);
-    var toolbarManager = new ToolbarManager(mockWindow, null, zoomToolbar);
+    const toolbarManager = new ToolbarManager(mockWindow, null, zoomToolbar);
    toolbarManager.getCurrentTimestamp_ = mockGetCurrentTimestamp;
    // Move the mouse and wait for a timeout to ensure toolbar is invisible.
@@ -223,13 +223,13 @@ var tests = [
   * device.
   */
  function testToolbarTouchInteraction() {
-    var mockWindow = new MockWindow(1920, 1080);
+    const mockWindow = new MockWindow(1920, 1080);
-    var toolbar = document.createElement('viewer-pdf-toolbar');
+    const toolbar = document.createElement('viewer-pdf-toolbar');
    toolbar.loadProgress = 100;
    document.body.appendChild(toolbar);
-    var zoomToolbar = document.createElement('viewer-zoom-toolbar');
+    const zoomToolbar = document.createElement('viewer-zoom-toolbar');
    document.body.appendChild(zoomToolbar);
-    var toolbarManager = new ToolbarManager(mockWindow, toolbar, zoomToolbar);
+    const toolbarManager = new ToolbarManager(mockWindow, toolbar, zoomToolbar);
    toolbarManager.hideToolbarsIfAllowed();
    chrome.test.assertFalse(toolbar.opened);

--- a/chrome/test/data/pdf/touch_handling_test.js
+++ b/chrome/test/data/pdf/touch_handling_test.js
@@ -3,9 +3,9 @@
 // found in the LICENSE file.
 function sendTouchStart(touches) {
-  var id = 0;
+  let id = 0;
-  let touchList = touches.map(function(xy) {
+  const touchList = touches.map(function(xy) {
-    var touchInit = {
+    const touchInit = {
      identifier: id++,
      target: viewer.plugin_,
      clientX: xy.x,
@@ -30,12 +30,12 @@ function createContextMenuEvent() {
  });
 }
-var tests = [
+const tests = [
  // Test suppression of the context menu on single touch.
  function testContextMenuSingleTouch() {
    sendTouchStart([{x: 10, y: 10}]);
-    let event = createContextMenuEvent();
+    const event = createContextMenuEvent();
    // Dispatch event will be false if the event is cancellable and one of the
    // handlers called preventDefault.
    chrome.test.assertFalse(
@@ -48,7 +48,7 @@ var tests = [
  function testContextMenuDoubleTouch() {
    sendTouchStart([{x: 10, y: 10}, {x: 15, y: 15}]);
-    let event = createContextMenuEvent();
+    const event = createContextMenuEvent();
    chrome.test.assertTrue(
        document.dispatchEvent(event),
        'Should not have called preventDefault() for double touch.');
@@ -73,7 +73,7 @@ var tests = [
  // }
 ];
-var scriptingAPI = new PDFScriptingAPI(window, window);
+const scriptingAPI = new PDFScriptingAPI(window, window);
 scriptingAPI.setLoadCallback(function() {
  chrome.test.runTests(tests);
 });
--- a/chrome/test/data/pdf/viewport_test.js
+++ b/chrome/test/data/pdf/viewport_test.js
@@ -7,11 +7,11 @@ import {Viewport} from 'chrome-extension://mhjfbmdgcfjbbpaeojofohoefgiehjai/view
 import {MockDocumentDimensions, MockSizer, MockViewportChangedCallback, MockWindow} from './test_util.js';
-var tests = [
+const tests = [
  function testDocumentNeedsScrollbars() {
-    var viewport =
+    let viewport =
        new Viewport(new MockWindow(100, 100), new MockSizer(), 10, 1, 0);
-    var scrollbars;
+    let scrollbars;
    viewport.setDocumentDimensions(new MockDocumentDimensions(90, 90));
    scrollbars = viewport.documentNeedsScrollbars_(1);
@@ -65,10 +65,9 @@ var tests = [
    chrome.test.succeed();
    // Test the case when there is a toolbar at the top.
-    var toolbarHeight = 10;
+    const toolbarHeight = 10;
-    var viewport = new Viewport(
+    viewport = new Viewport(
        new MockWindow(100, 100), new MockSizer(), 10, 1, toolbarHeight);
-    var scrollbars;
    viewport.setDocumentDimensions(new MockDocumentDimensions(90, 90));
    scrollbars = viewport.documentNeedsScrollbars_(1);
@@ -102,10 +101,10 @@ var tests = [
  },
  function testSetZoom() {
-    var mockSizer = new MockSizer();
+    const mockSizer = new MockSizer();
-    var mockWindow = new MockWindow(100, 100, mockSizer);
+    const mockWindow = new MockWindow(100, 100, mockSizer);
-    var mockCallback = new MockViewportChangedCallback();
+    const mockCallback = new MockViewportChangedCallback();
-    var viewport = new Viewport(mockWindow, mockSizer, 0, 1, 0);
+    const viewport = new Viewport(mockWindow, mockSizer, 0, 1, 0);
    viewport.setViewportChangedCallback(mockCallback.callback);
    // Test setting the zoom without the document dimensions set. The sizer
@@ -155,7 +154,7 @@ var tests = [
    chrome.test.assertEq(100, mockWindow.pageXOffset);
    chrome.test.assertEq(100, mockWindow.pageYOffset);
-    var documentDimensions = new MockDocumentDimensions(0, 0);
+    const documentDimensions = new MockDocumentDimensions(0, 0);
    documentDimensions.addPage(200, 200);
    viewport.setDocumentDimensions(documentDimensions);
    mockWindow.scrollTo(0, 0);
@@ -179,10 +178,10 @@ var tests = [
  },
  function testGetMostVisiblePage() {
-    var mockWindow = new MockWindow(100, 100);
+    const mockWindow = new MockWindow(100, 100);
-    var viewport = new Viewport(mockWindow, new MockSizer(), 0, 1, 0);
+    const viewport = new Viewport(mockWindow, new MockSizer(), 0, 1, 0);
-    var documentDimensions = new MockDocumentDimensions(100, 100);
+    const documentDimensions = new MockDocumentDimensions(100, 100);
    documentDimensions.addPage(50, 100);
    documentDimensions.addPage(100, 100);
    documentDimensions.addPage(100, 200);
@@ -239,11 +238,11 @@ var tests = [
  },
  function testGetMostVisiblePageForTwoUpView() {
-    var mockWindow = new MockWindow(400, 500);
+    const mockWindow = new MockWindow(400, 500);
-    var viewport = new Viewport(mockWindow, new MockSizer(), 0, 1, 0);
+    const viewport = new Viewport(mockWindow, new MockSizer(), 0, 1, 0);
    viewport.setTwoUpView(true);
-    var documentDimensions = new MockDocumentDimensions(100, 100);
+    const documentDimensions = new MockDocumentDimensions(100, 100);
    documentDimensions.addPageForTwoUpView(100, 0, 300, 400);
    documentDimensions.addPageForTwoUpView(400, 0, 400, 300);
    documentDimensions.addPageForTwoUpView(0, 400, 400, 250);
@@ -276,12 +275,12 @@ var tests = [
  },
  function testFitToWidth() {
-    var mockWindow = new MockWindow(100, 100);
+    const mockWindow = new MockWindow(100, 100);
-    var mockSizer = new MockSizer();
+    const mockSizer = new MockSizer();
-    var mockCallback = new MockViewportChangedCallback();
+    const mockCallback = new MockViewportChangedCallback();
-    var viewport = new Viewport(mockWindow, mockSizer, 0, 1, 0);
+    let viewport = new Viewport(mockWindow, mockSizer, 0, 1, 0);
    viewport.setViewportChangedCallback(mockCallback.callback);
-    var documentDimensions = new MockDocumentDimensions();
+    const documentDimensions = new MockDocumentDimensions();
    function assertZoomed(expectedMockWidth, expectedMockHeight, expectedZoom) {
      chrome.test.assertEq(FittingType.FIT_TO_WIDTH, viewport.fittingType);
@@ -351,12 +350,12 @@ var tests = [
  },
  function testFitToPage() {
-    var mockWindow = new MockWindow(100, 100);
+    const mockWindow = new MockWindow(100, 100);
-    var mockSizer = new MockSizer();
+    const mockSizer = new MockSizer();
-    var mockCallback = new MockViewportChangedCallback();
+    const mockCallback = new MockViewportChangedCallback();
-    var viewport = new Viewport(mockWindow, mockSizer, 0, 1, 0);
+    const viewport = new Viewport(mockWindow, mockSizer, 0, 1, 0);
    viewport.setViewportChangedCallback(mockCallback.callback);
-    var documentDimensions = new MockDocumentDimensions();
+    const documentDimensions = new MockDocumentDimensions();
    function assertZoomed(expectedMockWidth, expectedMockHeight, expectedZoom) {
      chrome.test.assertEq(FittingType.FIT_TO_PAGE, viewport.fittingType);
@@ -453,12 +452,12 @@ var tests = [
  },
  function testFitToHeight() {
-    var mockWindow = new MockWindow(100, 100);
+    const mockWindow = new MockWindow(100, 100);
-    var mockSizer = new MockSizer();
+    const mockSizer = new MockSizer();
-    var mockCallback = new MockViewportChangedCallback();
+    const mockCallback = new MockViewportChangedCallback();
-    var viewport = new Viewport(mockWindow, mockSizer, 0, 1, 0);
+    const viewport = new Viewport(mockWindow, mockSizer, 0, 1, 0);
    viewport.setViewportChangedCallback(mockCallback.callback);
-    var documentDimensions = new MockDocumentDimensions();
+    const documentDimensions = new MockDocumentDimensions();
    function assertZoomed(expectedMockWidth, expectedMockHeight, expectedZoom) {
      chrome.test.assertEq(FittingType.FIT_TO_HEIGHT, viewport.fittingType);
@@ -555,12 +554,12 @@ var tests = [
  },
  function testGoToNextPage() {
-    var mockWindow = new MockWindow(100, 100);
+    const mockWindow = new MockWindow(100, 100);
-    var mockSizer = new MockSizer();
+    const mockSizer = new MockSizer();
-    var mockCallback = new MockViewportChangedCallback();
+    const mockCallback = new MockViewportChangedCallback();
-    var viewport = new Viewport(mockWindow, mockSizer, 0, 1, 0);
+    const viewport = new Viewport(mockWindow, mockSizer, 0, 1, 0);
    viewport.setViewportChangedCallback(mockCallback.callback);
-    var documentDimensions = new MockDocumentDimensions();
+    const documentDimensions = new MockDocumentDimensions();
    documentDimensions.addPage(100, 100);
    documentDimensions.addPage(200, 200);
@@ -597,14 +596,14 @@ var tests = [
  },
  function testGoToNextPageInTwoUpView() {
-    var mockWindow = new MockWindow(100, 100);
+    const mockWindow = new MockWindow(100, 100);
-    var mockSizer = new MockSizer();
+    const mockSizer = new MockSizer();
-    var mockCallback = new MockViewportChangedCallback();
+    const mockCallback = new MockViewportChangedCallback();
-    var viewport = new Viewport(mockWindow, mockSizer, 0, 1, 0);
+    const viewport = new Viewport(mockWindow, mockSizer, 0, 1, 0);
    viewport.setViewportChangedCallback(mockCallback.callback);
    viewport.setTwoUpView(true);
-    var documentDimensions = new MockDocumentDimensions(800, 750);
+    const documentDimensions = new MockDocumentDimensions(800, 750);
    documentDimensions.addPageForTwoUpView(200, 0, 200, 150);
    documentDimensions.addPageForTwoUpView(400, 0, 400, 200);
    documentDimensions.addPageForTwoUpView(100, 200, 300, 250);
@@ -660,12 +659,12 @@ var tests = [
  },
  function testGoToPreviousPage() {
-    var mockWindow = new MockWindow(100, 100);
+    const mockWindow = new MockWindow(100, 100);
-    var mockSizer = new MockSizer();
+    const mockSizer = new MockSizer();
-    var mockCallback = new MockViewportChangedCallback();
+    const mockCallback = new MockViewportChangedCallback();
-    var viewport = new Viewport(mockWindow, mockSizer, 0, 1, 0);
+    const viewport = new Viewport(mockWindow, mockSizer, 0, 1, 0);
    viewport.setViewportChangedCallback(mockCallback.callback);
-    var documentDimensions = new MockDocumentDimensions();
+    const documentDimensions = new MockDocumentDimensions();
    documentDimensions.addPage(100, 100);
    documentDimensions.addPage(200, 200);
@@ -702,14 +701,14 @@ var tests = [
  },
  function testGoToPreviousPageInTwoUpView() {
-    var mockWindow = new MockWindow(100, 100);
+    const mockWindow = new MockWindow(100, 100);
-    var mockSizer = new MockSizer();
+    const mockSizer = new MockSizer();
-    var mockCallback = new MockViewportChangedCallback();
+    const mockCallback = new MockViewportChangedCallback();
-    var viewport = new Viewport(mockWindow, mockSizer, 0, 1, 0);
+    const viewport = new Viewport(mockWindow, mockSizer, 0, 1, 0);
    viewport.setViewportChangedCallback(mockCallback.callback);
    viewport.setTwoUpView(true);
-    var documentDimensions = new MockDocumentDimensions(800, 750);
+    const documentDimensions = new MockDocumentDimensions(800, 750);
    documentDimensions.addPageForTwoUpView(200, 0, 200, 150);
    documentDimensions.addPageForTwoUpView(400, 0, 400, 200);
    documentDimensions.addPageForTwoUpView(100, 200, 300, 250);
@@ -766,12 +765,12 @@ var tests = [
  },
  function testGoToPage() {
-    var mockWindow = new MockWindow(100, 100);
+    const mockWindow = new MockWindow(100, 100);
-    var mockSizer = new MockSizer();
+    const mockSizer = new MockSizer();
-    var mockCallback = new MockViewportChangedCallback();
+    const mockCallback = new MockViewportChangedCallback();
-    var viewport = new Viewport(mockWindow, mockSizer, 0, 1, 0);
+    const viewport = new Viewport(mockWindow, mockSizer, 0, 1, 0);
    viewport.setViewportChangedCallback(mockCallback.callback);
-    var documentDimensions = new MockDocumentDimensions();
+    const documentDimensions = new MockDocumentDimensions();
    documentDimensions.addPage(100, 100);
    documentDimensions.addPage(200, 200);
@@ -807,12 +806,12 @@ var tests = [
  },
  function testGoToPageAndXY() {
-    var mockWindow = new MockWindow(100, 100);
+    const mockWindow = new MockWindow(100, 100);
-    var mockSizer = new MockSizer();
+    const mockSizer = new MockSizer();
-    var mockCallback = new MockViewportChangedCallback();
+    const mockCallback = new MockViewportChangedCallback();
-    var viewport = new Viewport(mockWindow, mockSizer, 0, 1, 0);
+    const viewport = new Viewport(mockWindow, mockSizer, 0, 1, 0);
    viewport.setViewportChangedCallback(mockCallback.callback);
-    var documentDimensions = new MockDocumentDimensions();
+    const documentDimensions = new MockDocumentDimensions();
    documentDimensions.addPage(100, 100);
    documentDimensions.addPage(200, 200);
@@ -860,12 +859,12 @@ var tests = [
  },
  function testScrollTo() {
-    var mockWindow = new MockWindow(100, 100);
+    const mockWindow = new MockWindow(100, 100);
-    var mockSizer = new MockSizer();
+    const mockSizer = new MockSizer();
-    var mockCallback = new MockViewportChangedCallback();
+    const mockCallback = new MockViewportChangedCallback();
-    var viewport = new Viewport(mockWindow, mockSizer, 0, 1, 0);
+    const viewport = new Viewport(mockWindow, mockSizer, 0, 1, 0);
    viewport.setViewportChangedCallback(mockCallback.callback);
-    var documentDimensions = new MockDocumentDimensions();
+    const documentDimensions = new MockDocumentDimensions();
    documentDimensions.addPage(200, 200);
    viewport.setDocumentDimensions(documentDimensions);
@@ -914,12 +913,12 @@ var tests = [
  },
  function testScrollBy() {
-    var mockWindow = new MockWindow(100, 100);
+    const mockWindow = new MockWindow(100, 100);
-    var mockSizer = new MockSizer();
+    const mockSizer = new MockSizer();
-    var mockCallback = new MockViewportChangedCallback();
+    const mockCallback = new MockViewportChangedCallback();
-    var viewport = new Viewport(mockWindow, mockSizer, 0, 1, 0);
+    const viewport = new Viewport(mockWindow, mockSizer, 0, 1, 0);
    viewport.setViewportChangedCallback(mockCallback.callback);
-    var documentDimensions = new MockDocumentDimensions();
+    const documentDimensions = new MockDocumentDimensions();
    documentDimensions.addPage(200, 200);
    viewport.setDocumentDimensions(documentDimensions);
@@ -962,12 +961,12 @@ var tests = [
  },
  function testGetPageScreenRect() {
-    var mockWindow = new MockWindow(100, 100);
+    const mockWindow = new MockWindow(100, 100);
-    var mockSizer = new MockSizer();
+    const mockSizer = new MockSizer();
-    var mockCallback = new MockViewportChangedCallback();
+    const mockCallback = new MockViewportChangedCallback();
-    var viewport = new Viewport(mockWindow, mockSizer, 0, 1, 0);
+    const viewport = new Viewport(mockWindow, mockSizer, 0, 1, 0);
    viewport.setViewportChangedCallback(mockCallback.callback);
-    var documentDimensions = new MockDocumentDimensions();
+    const documentDimensions = new MockDocumentDimensions();
    documentDimensions.addPage(100, 100);
    documentDimensions.addPage(200, 200);
    viewport.setDocumentDimensions(documentDimensions);
@@ -975,7 +974,7 @@ var tests = [
    // Test that the rect of the first page is positioned/sized correctly.
    mockWindow.scrollTo(0, 0);
-    var rect1 = viewport.getPageScreenRect(0);
+    let rect1 = viewport.getPageScreenRect(0);
    chrome.test.assertEq(Viewport.PAGE_SHADOW.left + 100 / 2, rect1.x);
    chrome.test.assertEq(Viewport.PAGE_SHADOW.top, rect1.y);
    chrome.test.assertEq(
@@ -988,7 +987,7 @@ var tests = [
    // Check that when we scroll, the rect of the first page is updated
    // correctly.
    mockWindow.scrollTo(100, 10);
-    var rect2 = viewport.getPageScreenRect(0);
+    const rect2 = viewport.getPageScreenRect(0);
    chrome.test.assertEq(rect1.x - 100, rect2.x);
    chrome.test.assertEq(rect1.y - 10, rect2.y);
    chrome.test.assertEq(rect1.width, rect2.width);
@@ -1009,22 +1008,23 @@ var tests = [
  },
  function testBeforeZoomAfterZoom() {
-    var mockWindow = new MockWindow(100, 100);
+    const mockWindow = new MockWindow(100, 100);
-    var mockSizer = new MockSizer();
+    const mockSizer = new MockSizer();
-    var viewport;
+    const viewport = new Viewport(mockWindow, mockSizer, 0, 1, 0);
-    var afterZoomCalled = false;
-    var beforeZoomCalled = false;
+    let afterZoomCalled = false;
-    var afterZoom = function() {
+    let beforeZoomCalled = false;
+    const afterZoom = function() {
      afterZoomCalled = true;
      chrome.test.assertTrue(beforeZoomCalled);
      chrome.test.assertEq(0.5, viewport.getZoom());
    };
-    var beforeZoom = function() {
+    const beforeZoom = function() {
      beforeZoomCalled = true;
      chrome.test.assertFalse(afterZoomCalled);
      chrome.test.assertEq(1, viewport.getZoom());
    };
-    viewport = new Viewport(mockWindow, mockSizer, 0, 1, 0);
    viewport.setBeforeZoomCallback(beforeZoom);
    viewport.setAfterZoomCallback(afterZoom);
    viewport.setZoom(0.5);
@@ -1032,7 +1032,7 @@ var tests = [
  },
  function testInitialSetDocumentDimensionsZoomConstrained() {
-    var viewport =
+    const viewport =
        new Viewport(new MockWindow(100, 100), new MockSizer(), 0, 1.2, 0);
    viewport.setDocumentDimensions(new MockDocumentDimensions(50, 50));
    chrome.test.assertEq(1.2, viewport.getZoom());
@@ -1040,7 +1040,7 @@ var tests = [
  },
  function testInitialSetDocumentDimensionsZoomUnconstrained() {
-    var viewport =
+    const viewport =
        new Viewport(new MockWindow(100, 100), new MockSizer(), 0, 3, 0);
    viewport.setDocumentDimensions(new MockDocumentDimensions(50, 50));
    chrome.test.assertEq(2, viewport.getZoom());
@@ -1048,7 +1048,7 @@ var tests = [
  },
  function testLayoutOptions() {
-    var viewport =
+    const viewport =
        new Viewport(new MockWindow(100, 100), new MockSizer(), 0, 1, 0);
    chrome.test.assertEq(undefined, viewport.getLayoutOptions());
@@ -1065,10 +1065,10 @@ var tests = [
  },
  function testToolbarHeightOffset() {
-    var mockSizer = new MockSizer();
+    const mockSizer = new MockSizer();
-    var mockWindow = new MockWindow(100, 100);
+    const mockWindow = new MockWindow(100, 100);
-    var viewport = new Viewport(mockWindow, mockSizer, 0, 1, 50);
+    const viewport = new Viewport(mockWindow, mockSizer, 0, 1, 50);
-    var documentDimensions = new MockDocumentDimensions(0, 0);
+    const documentDimensions = new MockDocumentDimensions(0, 0);
    documentDimensions.addPage(50, 500);
    viewport.setDocumentDimensions(documentDimensions);
    viewport.setZoom(1);

--- a/chrome/test/data/pdf/whitespace_title_test.js
+++ b/chrome/test/data/pdf/whitespace_title_test.js
@@ -2,7 +2,7 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
-var tests = [
+const tests = [
  /**
   * Test that the correct title is displayed for test-whitespace-title.pdf.
   */
@@ -13,7 +13,7 @@ var tests = [
  }
 ];
-var scriptingAPI = new PDFScriptingAPI(window, window);
+const scriptingAPI = new PDFScriptingAPI(window, window);
 scriptingAPI.setLoadCallback(function() {
  chrome.test.runTests(tests);
 });
--- a/chrome/test/data/pdf/zoom_manager_test.js
+++ b/chrome/test/data/pdf/zoom_manager_test.js
@@ -88,9 +88,9 @@ chrome.test.runTests(function() {
  return [
    function testZoomChange() {
-      let viewport = new MockViewport();
+      const viewport = new MockViewport();
-      let browserZoomSetter = new MockBrowserZoomSetter();
+      const browserZoomSetter = new MockBrowserZoomSetter();
-      let zoomManager = ZoomManager.create(
+      const zoomManager = ZoomManager.create(
          BrowserApi.ZoomBehavior.MANAGE, () => viewport.getZoom(),
          zoom => browserZoomSetter.setBrowserZoom(zoom), 1);
      viewport.addZoomListeners(zoomManager.getEventTarget());
@@ -103,8 +103,8 @@ chrome.test.runTests(function() {
    },
    function testBrowserZoomChange() {
-      let viewport = new MockViewport();
+      const viewport = new MockViewport();
-      let zoomManager = ZoomManager.create(
+      const zoomManager = ZoomManager.create(
          BrowserApi.ZoomBehavior.MANAGE, () => viewport.getZoom(),
          chrome.test.fail, 1);
      viewport.addZoomListeners(zoomManager.getEventTarget());
@@ -117,8 +117,8 @@ chrome.test.runTests(function() {
    },
    function testBrowserZoomChangeEmbedded() {
-      let viewport = new MockViewport();
+      const viewport = new MockViewport();
-      let zoomManager = ZoomManager.create(
+      const zoomManager = ZoomManager.create(
          BrowserApi.ZoomBehavior.PROPAGATE_PARENT,
          () => viewport.getZoom(), function() {
            return Promise.reject();
@@ -137,9 +137,9 @@ chrome.test.runTests(function() {
    },
    function testSmallZoomChange() {
-      let viewport = new MockViewport();
+      const viewport = new MockViewport();
-      let browserZoomSetter = new MockBrowserZoomSetter();
+      const browserZoomSetter = new MockBrowserZoomSetter();
-      let zoomManager = ZoomManager.create(
+      const zoomManager = ZoomManager.create(
          BrowserApi.ZoomBehavior.MANAGE, () => viewport.getZoom(),
          zoom => browserZoomSetter.setBrowserZoom(zoom), 2);
      viewport.addZoomListeners(zoomManager.getEventTarget());
@@ -152,8 +152,8 @@ chrome.test.runTests(function() {
    },
    function testSmallBrowserZoomChange() {
-      let viewport = new MockViewport();
+      const viewport = new MockViewport();
-      let zoomManager = ZoomManager.create(
+      const zoomManager = ZoomManager.create(
          BrowserApi.ZoomBehavior.MANAGE, () => viewport.getZoom(),
          chrome.test.fail, 1);
      viewport.addZoomListeners(zoomManager.getEventTarget());
@@ -165,9 +165,9 @@ chrome.test.runTests(function() {
    },
    function testMultiplePdfZoomChanges() {
-      let viewport = new MockViewport();
+      const viewport = new MockViewport();
-      let browserZoomSetter = new MockBrowserZoomSetter();
+      const browserZoomSetter = new MockBrowserZoomSetter();
-      let zoomManager = ZoomManager.create(
+      const zoomManager = ZoomManager.create(
          BrowserApi.ZoomBehavior.MANAGE, () => viewport.getZoom(),
          zoom => browserZoomSetter.setBrowserZoom(zoom), 1);
      viewport.addZoomListeners(zoomManager.getEventTarget());
@@ -187,8 +187,8 @@ chrome.test.runTests(function() {
    },
    function testMultipleBrowserZoomChanges() {
-      let viewport = new MockViewport();
+      const viewport = new MockViewport();
-      let zoomManager = ZoomManager.create(
+      const zoomManager = ZoomManager.create(
          BrowserApi.ZoomBehavior.MANAGE, () => viewport.getZoom(),
          chrome.test.fail, 1);
      viewport.addZoomListeners(zoomManager.getEventTarget());