Convert accessibility common to use ES6 modules

R=dmazzoni@chromium.org, josiahk@chromium.org

AX-Relnotes: n/a
Test: existing browser_tests
Change-Id: Ifc2b85ac0903903f8cc526e4a2154121da8346f2
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2602108Reviewed-by: Josiah Krutz <josiahk@chromium.org>
Commit-Queue: David Tseng <dtseng@chromium.org>
Cr-Commit-Position: refs/heads/master@{#839141}

chrome/browser/resources/chromeos/accessibility/accessibility_common/BUILD.gn

@@ -26,6 +26,7 @@ run_jsbundler("accessibility_common_copied_files") {
   sources = [
     "accessibility_common_loader.js",
     "autoclick/autoclick.js",
+    "background.html",
     "magnifier/magnifier.js",
   ]
   rewrite_rules = [

chrome/browser/resources/chromeos/accessibility/accessibility_common/accessibility_common_loader.js

@@ -2,11 +2,14 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
+import {Autoclick} from './autoclick/autoclick.js';
+import {Magnifier} from './magnifier/magnifier.js';
+
 /**
  * Class to manage loading resources depending on which Accessibility features
  * are enabled.
  */
-class AccessibilityCommon {
+export class AccessibilityCommon {
   constructor() {
     /** @private {Autoclick} */
     this.autoclick_ = null;
@@ -86,4 +89,4 @@ class AccessibilityCommon {
 
 InstanceChecker.closeExtraInstances();
 // Initialize the AccessibilityCommon extension.
-var accessibilityCommon = new AccessibilityCommon();
+window.accessibilityCommon = new AccessibilityCommon();

chrome/browser/resources/chromeos/accessibility/accessibility_common/autoclick/autoclick.js

@@ -19,7 +19,7 @@ const AUTOCLICK_FOCUS_RING_DISPLAY_TIME_MS = 250;
 /**
  * Class to manage Automatic Clicks' interaction with the accessibility tree.
  */
-class Autoclick {
+export class Autoclick {
   constructor() {
     /**
      * Whether to blink the focus rings. Disabled during tests due to

chrome/browser/resources/chromeos/accessibility/accessibility_common/autoclick/autoclick_test.js

@@ -18,12 +18,16 @@ AutoclickE2ETest = class extends E2ETestBase {
     window.RoleType = chrome.automation.RoleType;
 
     // Re-initialize AccessibilityCommon with mock AccessibilityPrivate API.
-    accessibilityCommon = new AccessibilityCommon();
-
+    const reinit = module => {
+      accessibilityCommon = new module.AccessibilityCommon();
       chrome.accessibilityFeatures.autoclick.get({}, () => {
         // Turn off focus ring blinking for test after autoclick is initialized.
         accessibilityCommon.getAutoclickForTest().setNoBlinkFocusRingsForTest();
       });
+    };
+
+// TODO: Clang-format does this and below wrong.
+import('/accessibility_common/accessibility_common_loader.js').then(reinit);
   }
 
   /** @override */

chrome/browser/resources/chromeos/accessibility/accessibility_common/background.html

+<!-- Global scripts. -->
+<script src="/common/closure_shim.js"></script>
+<script src="/common/instance_checker.js"></script>
+<script src="/common/event_handler.js"></script>
+
+<!-- Module entry point. -->
+<script type="module" src="accessibility_common_loader.js"></script>

chrome/browser/resources/chromeos/accessibility/accessibility_common/magnifier/magnifier.js

@@ -5,7 +5,7 @@
 /**
  * Main class for the Chrome OS magnifier.
  */
-class Magnifier {
+export class Magnifier {
   /**
    * @param {!Magnifier.Type} type The type of magnifier in use.
    */

chrome/browser/resources/chromeos/accessibility/accessibility_common/magnifier/magnifier_test.js

@@ -174,6 +174,9 @@ TEST_F(
 
 TEST_F('MagnifierE2ETest', 'ScreenMagnifierFocusFollowingPref', function() {
   this.newCallback(async () => {
+    const module = await import('/accessibility_common/magnifier/magnifier.js');
+    const Magnifier = module.Magnifier;
+
     // Disable focus following for full screen magnifier, and verify prefs and
     // state.
     await this.setPref(Magnifier.Prefs.SCREEN_MAGNIFIER_FOCUS_FOLLOWING, false);

chrome/browser/resources/chromeos/accessibility/accessibility_common_manifest.json.jinja2

@@ -10,14 +10,7 @@
   "incognito": "split",
 {% endif %}
   "background": {
-    "scripts": [
-      "common/closure_shim.js",
-      "common/instance_checker.js",
-      "accessibility_common/autoclick/autoclick.js",
-      "accessibility_common/magnifier/magnifier.js",
-      "accessibility_common/accessibility_common_loader.js",
-      "common/event_handler.js"
-    ]
+    "page": "accessibility_common/background.html"
   },
   "permissions": [
     "accessibilityPrivate",