Docked Magnifier Sends OnMagnifierBoundsChanged Events

AX-Relnotes: N/A
Bug: 1151216
Change-Id: I222ec5d29ae2fd06689d6d94876f4fa6973e4c2a
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2552163
Commit-Queue: Josiah Krutz <josiahk@google.com>
Reviewed-by: Ahmed Fakhry <afakhry@chromium.org>
Reviewed-by: David Tseng <dtseng@chromium.org>
Cr-Commit-Position: refs/heads/master@{#830905}

ash/magnifier/docked_magnifier_controller_impl.cc

@@ -235,8 +235,9 @@ void DockedMagnifierControllerImpl::CenterOnPoint(
   // 1- Scale the layer by |scale|.
   // 2- Translate the point of interest to the center point of the viewport
   //    widget.
-  const gfx::Point viewport_center_point =
-      GetViewportWidgetBoundsInRoot(current_source_root_window_).CenterPoint();
+  const gfx::Rect viewport_widget_bounds =
+      GetViewportWidgetBoundsInRoot(current_source_root_window_);
+  const gfx::Point viewport_center_point = viewport_widget_bounds.CenterPoint();
   gfx::Transform transform;
   transform.Translate(viewport_center_point.x() - point_in_pixels.x(),
                       viewport_center_point.y() - point_in_pixels.y());
@@ -252,6 +253,29 @@ void DockedMagnifierControllerImpl::CenterOnPoint(
   settings.SetTweenType(gfx::Tween::ZERO);
   settings.SetPreemptionStrategy(ui::LayerAnimator::IMMEDIATELY_SET_NEW_TARGET);
   viewport_magnifier_layer_->SetTransform(transform);
+
+  // Also make sure |point_of_interest|'s y-coordinate doesn't go below
+  // the minimum height.
+  if (point_of_interest.y() < minimum_point_of_interest_height_)
+    point_of_interest.set_y(minimum_point_of_interest_height_);
+
+  // Send changed magnified region bounds to accessibility controller,
+  // triggering accessibility manager to dispatch an accessibility private
+  // OnMagnifierBoundsChanged event, which will be listened for by magnifier.js,
+  // which keeps track of the last magnified region bounds, to help when
+  // deciding where to next move the magnified region.
+  // |viewport_widget_bounds| represents the full-width docked magnifier panel
+  // at the top of the screen. Shrink this by the current magnifier |scale| to
+  // get the actual zoomed-in width and height of the magnified area.
+  const int width = viewport_widget_bounds.width() / scale;
+  const int height = viewport_widget_bounds.height() / scale;
+  const int x = point_of_interest.x() - width / 2;
+  const int y = point_of_interest.y() - height / 2;
+  gfx::Rect magnified_region_bounds(x, y, width, height);
+  ::wm::ConvertRectToScreen(root_window, &magnified_region_bounds);
+
+  Shell::Get()->accessibility_controller()->MagnifierBoundsChanged(
+      magnified_region_bounds);
 }
 
 int DockedMagnifierControllerImpl::GetMagnifierHeightForTesting() const {

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

@@ -61,6 +61,7 @@ js2gtest("accessibility_common_extjs_tests") {
   sources = [
     "accessibility_common_test.js",
     "autoclick/autoclick_test.js",
+    "magnifier/docked_magnifier_test.js",
     "magnifier/magnifier_test.js",
   ]
   gen_include_files = [
@@ -68,6 +69,7 @@ js2gtest("accessibility_common_extjs_tests") {
     "../common/testing/callback_helper.js",
     "../common/testing/e2e_test_base.js",
     "../common/testing/mock_accessibility_private.js",
+    "magnifier/magnifier_test_common.js",
   ]
 
   # The test base classes generate C++ code with these deps.

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

+// Copyright 2020 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+GEN_INCLUDE(['../../common/testing/e2e_test_base.js']);
+GEN_INCLUDE(['../../common/testing/mock_accessibility_private.js']);
+GEN_INCLUDE(['../../common/rect_util.js']);
+GEN_INCLUDE(['magnifier_test_common.js']);
+
+/**
+ * Magnifier feature using accessibility common extension browser tests.
+ */
+DockedMagnifierE2ETest = class extends E2ETestBase {
+  constructor() {
+    super();
+    window.RoleType = chrome.automation.RoleType;
+  }
+
+  async getNextMagnifierBounds() {
+    return new Promise(resolve => {
+      const listener = (magnifierBounds) => {
+        chrome.accessibilityPrivate.onMagnifierBoundsChanged.removeListener(
+            listener);
+        resolve(magnifierBounds);
+      };
+      chrome.accessibilityPrivate.onMagnifierBoundsChanged.addListener(
+          listener);
+    });
+  }
+
+  /** @override */
+  testGenCppIncludes() {
+    super.testGenCppIncludes();
+    GEN(`
+#include "chrome/browser/chromeos/accessibility/magnification_manager.h"
+#include "chrome/common/extensions/extension_constants.h"
+#include "content/public/test/browser_test.h"
+    `);
+  }
+
+  /** @override */
+  testGenPreamble() {
+    super.testGenPreamble();
+    GEN(`
+    base::Closure load_cb =
+        base::Bind(&chromeos::MagnificationManager::SetDockedMagnifierEnabled,
+            base::Unretained(chromeos::MagnificationManager::Get()),
+            true);
+    WaitForExtension(extension_misc::kAccessibilityCommonExtensionId, load_cb);
+      `);
+  }
+};
+
+TEST_F(
+    'DockedMagnifierE2ETest', 'MovesDockedMagnifierToActiveDescendant',
+    function() {
+      this.runWithLoadedTree(ActiveDescendantSite, async function(root) {
+        const top = root.find({attributes: {name: 'Top'}});
+        const banana = root.find({attributes: {name: 'Banana'}});
+        const group = root.find({role: RoleType.GROUP});
+
+        // Focus and move magnifier to top.
+        top.focus();
+
+        // Verify magnifier contain top and not banana.
+        let bounds = await this.getNextMagnifierBounds();
+        assertTrue(RectUtil.contains(bounds, top.location));
+        assertFalse(RectUtil.contains(bounds, banana.location));
+
+        // Click group to change active descendant to banana.
+        group.doDefault();
+
+        // Verify magnifier bounds contain banana.
+        bounds = await this.getNextMagnifierBounds();
+        assertFalse(RectUtil.contains(bounds, top.location));
+        assertTrue(RectUtil.contains(bounds, banana.location));
+      });
+    });

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

@@ -5,6 +5,7 @@
 GEN_INCLUDE(['../../common/testing/e2e_test_base.js']);
 GEN_INCLUDE(['../../common/testing/mock_accessibility_private.js']);
 GEN_INCLUDE(['../../common/rect_util.js']);
+GEN_INCLUDE(['magnifier_test_common.js']);
 
 /**
  * Magnifier feature using accessibility common extension browser tests.
@@ -77,64 +78,9 @@ TEST_F('MagnifierE2ETest', 'MovesScreenMagnifierToFocusedElement', function() {
   });
 });
 
-// Disabled - flaky: https://crbug.com/1145612
-TEST_F(
-    'MagnifierE2ETest', 'DISABLED_MovesDockedMagnifierToActiveDescendant', function() {
-      const site = `
-    <div role="group" id="parent" aria-activedescendant="apple">
-      <div id="apple" role="treeitem">Apple</div>
-      <div id="banana" role="treeitem">Banana</div>
-    </div>
-    <script>
-      const parent = document.getElementById('parent');
-      parent.addEventListener('click', function() {
-        parent.setAttribute('aria-activedescendant', 'banana');
-      });
-      </script>
-  `;
-      this.runWithLoadedTree(site, async function(root) {
-        // Enable docked magnifier.
-        await new Promise(resolve => {
-          chrome.accessibilityFeatures.dockedMagnifier.set(
-              {value: true}, resolve);
-        });
-
-        // Validate magnifier wants to move to root.
-        const rootLocation = await getNextMagnifierLocation();
-        assertTrue(RectUtil.equal(rootLocation, root.location));
-
-        // Click parent to change active descendant from apple to banana.
-        const parent = root.find({role: RoleType.GROUP});
-        parent.doDefault();
-
-        // Register and wait for rect from magnifier.
-        const rect = await getNextMagnifierLocation();
-
-        // Validate rect from magnifier is rect of banana.
-        const bananaNode =
-            root.find({role: RoleType.TREE_ITEM, attributes: {name: 'Banana'}});
-        assertTrue(RectUtil.equal(rect, bananaNode.location));
-      }, {returnPage: true});
-    });
-
-
 TEST_F(
     'MagnifierE2ETest', 'MovesScreenMagnifierToActiveDescendant', function() {
-      const site = `
-    <span tabindex="1">Top</span>
-    <div id="group" role="group" style="width: 200px"
-        aria-activedescendant="apple">
-      <div id="apple" role="treeitem">Apple</div>
-      <div id="banana" role="treeitem" style="margin-top: 400px">Banana</div>
-    </div>
-    <script>
-      const group = document.getElementById('group');
-      group.addEventListener('click', function() {
-        group.setAttribute('aria-activedescendant', 'banana');
-      });
-    </script>
-  `;
-      this.runWithLoadedTree(site, async function(root) {
+      this.runWithLoadedTree(ActiveDescendantSite, async function(root) {
         const top = root.find({attributes: {name: 'Top'}});
         const banana = root.find({attributes: {name: 'Banana'}});
         const group = root.find({role: RoleType.GROUP});

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

+// Copyright 2020 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+const ActiveDescendantSite = `
+  <span tabindex="1">Top</span>
+  <div id="group" role="group" style="width: 200px"
+      aria-activedescendant="apple">
+    <div id="apple" role="treeitem">Apple</div>
+    <div id="banana" role="treeitem" style="margin-top: 400px">
+      Banana
+    </div>
+  </div>
+  <script>
+    const group = document.getElementById('group');
+    group.addEventListener('click', function() {
+      group.setAttribute('aria-activedescendant', 'banana');
+    });
+  </script>
+`;