Reland "Reland: [Accessibility] Volume slider reads out level in percentages."

This is a reland of d018c076

Original change's description:
> Reland: [Accessibility] Volume slider reads out level in percentages.
>
> This is a reland of change I0ee5a91215669f39c7394d3c8f113ae83a74cf00
>
> This CL makes it such that the volume level is read out as a percentage
> in aria. This CL also amplifies how the accessibility information is
> given to aria, by setting attributes instead of explicitly creating
> accessibility nodes.
>
> TBR=thakis@chromium.org
>
> Bug: 905024
> Change-Id: I831d9ed1f1790556d1a58431f3aaf9562c2c9043
> Reviewed-on: https://chromium-review.googlesource.com/c/1373032
> Reviewed-by: CJ DiMeglio <lethalantidote@chromium.org>
> Reviewed-by: Dominic Mazzoni <dmazzoni@chromium.org>
> Reviewed-by: Mounir Lamouri <mlamouri@chromium.org>
> Commit-Queue: CJ DiMeglio <lethalantidote@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#617338}

TBR=thakis@chromium.org,dmazzoni@chromium.org,mlamouri@chromium.org

Bug: 905024
Change-Id: Ie308a4b30032491333072681fcf214a9fab58d5c
Reviewed-on: https://chromium-review.googlesource.com/c/1383307Reviewed-by: CJ DiMeglio <lethalantidote@chromium.org>
Reviewed-by: Dominic Mazzoni <dmazzoni@chromium.org>
Commit-Queue: CJ DiMeglio <lethalantidote@chromium.org>
Cr-Commit-Position: refs/heads/master@{#618940}

content/browser/accessibility/dump_accessibility_tree_browsertest.cc

@@ -27,6 +27,7 @@
 #include "content/public/test/content_browser_test_utils.h"
 #include "content/shell/browser/shell.h"
 #include "content/test/accessibility_browser_test_utils.h"
+#include "ui/base/ui_base_features.h"
 
 #if defined(OS_MACOSX)
 #include "base/mac/mac_util.h"
@@ -1882,6 +1883,13 @@ IN_PROC_BROWSER_TEST_F(DumpAccessibilityTreeTest, DISABLED_AccessibilityVideo) {
   RunHtmlTest(FILE_PATH_LITERAL("video.html"));
 }
 
+IN_PROC_BROWSER_TEST_F(DumpAccessibilityTreeTest, AccessibilityVideoControls) {
+  // TODO(crbug.com/916003): fix for mash.
+  if (features::IsSingleProcessMash())
+    return;
+  RunHtmlTest(FILE_PATH_LITERAL("video-controls.html"));
+}
+
 IN_PROC_BROWSER_TEST_F(DumpAccessibilityTreeTest, AccessibilityWbr) {
   RunHtmlTest(FILE_PATH_LITERAL("wbr.html"));
 }

content/test/data/accessibility/html/video-controls-expected-auralinux.txt

+[document web]
+++[section]
+++++[video]
+++++++[section]
+++++++++[tool bar] name='video' description='video' horizontal
+++++++++[tool bar] name='video' description='video' horizontal
+++++++++++[tool bar] name='video' description='video' horizontal
+++++++++++++[tool bar] name='video' description='video' horizontal
+++++++++++++++[push button] name='play'
+++++++++++++++[text] name='0:00'
+++++++++++++++[section]
+++++++++++++++++[section]
+++++++++++++++++[push button] name='mute'
+++++++++++++++[push button] name='enter full screen'
+++++++++++++++[push button] name='show more media controls' description='more options'
+++++++++++++[slider] description='movie time scrubber' horizontal

content/test/data/accessibility/html/video-controls-expected-blink.txt

+rootWebArea
+++genericContainer
+++++video
+++++++genericContainer
+++++++++toolbar horizontal description='video' name='video' descriptionFrom=uninitialized
+++++++++toolbar horizontal description='video' name='video' descriptionFrom=uninitialized
+++++++++++toolbar horizontal description='video' name='video' descriptionFrom=uninitialized
+++++++++++++toolbar horizontal description='video' name='video' descriptionFrom=uninitialized
+++++++++++++++button name='play' restriction=disabled
+++++++++++++++staticText name='0:00'
+++++++++++++++++inlineTextBox name='0:00'
+++++++++++++++genericContainer
+++++++++++++++++genericContainer
+++++++++++++++++button name='mute' restriction=disabled
+++++++++++++++button name='enter full screen' restriction=disabled
+++++++++++++++button description='more options' name='show more media controls' descriptionFrom=uninitialized restriction=disabled
+++++++++++++slider horizontal description='movie time scrubber' value='0:00' descriptionFrom=uninitialized valueForRange=0.00 minValueForRange=0.00 maxValueForRange=0.00
+++++++++++++++sliderThumb

content/test/data/accessibility/html/video-controls.html

+<!DOCTYPE html>
+<html>
+  <body>
+    <video controls></video>
+  </body>
+</html>

third_party/WebKit/LayoutTests/media/controls/accessibility-volume-slider.html

+<!DOCTYPE html>
+<title>Media Controls: volume slider accessibility tests</title>
+<script src="../../resources/testharness.js"></script>
+<script src="../../resources/testharnessreport.js"></script>
+<script src="../media-controls.js"></script>
+<video controls></video>
+<script>
+async_test(t => {
+  // Ensure that we will show the volume slider.
+  setPreferHiddenVolumeControlsForTest(t, false);
+
+  assert_true(internals.runtimeFlags.accessibilityObjectModelEnabled);
+
+  var video = document.querySelector('video');
+  video.src = '../content/test.ogv';
+
+  video.onloadedmetadata = t.step(function() {
+
+    var volume_slider = volumeSliderElement(video);
+    assert_not_equals(volume_slider, null);
+
+    assert_equals(volume_slider.getAttribute('aria-label'), 'volume');
+    assert_equals(volume_slider.getAttribute('aria-valuemin'), '0');
+    assert_equals(volume_slider.getAttribute('aria-valuemax'), '100');
+    assert_equals(volume_slider.getAttribute('aria-valuenow'), '100');
+
+    // Trigger events that will update the timeline internal state.
+    video.volume = 0.54;
+    video.onvolumechange = t.step_func_done(function(event) {
+      assert_equals(volume_slider.getAttribute('aria-valuenow'), '54');
+    });
+  });
+});
+</script>

third_party/blink/renderer/modules/accessibility/ax_media_controls.cc

@@ -58,10 +58,6 @@ AXObject* AccessibilityMediaControl::Create(
     case kMediaSlider:
       return AccessibilityMediaTimeline::Create(layout_object, ax_object_cache);
 
-    case kMediaVolumeSlider:
-      return AccessibilityMediaVolumeSlider::Create(layout_object,
-                                                    ax_object_cache);
-
     case kMediaCurrentTimeDisplay:
     case kMediaTimeRemainingDisplay:
       return AccessibilityMediaTimeDisplay::Create(layout_object,
@@ -98,6 +94,11 @@ AXObject* AccessibilityMediaControl::Create(
     case kMediaAnimatedArrowContainer:
       return MakeGarbageCollected<AccessibilityMediaControl>(layout_object,
                                                              ax_object_cache);
+    // Removed as a part of the a11y tree rewrite https://crbug.com/836549.
+    case kMediaVolumeSlider:
+      NOTREACHED();
+      return MakeGarbageCollected<AccessibilityMediaControl>(layout_object,
+                                                             ax_object_cache);
   }
 
   NOTREACHED();
@@ -371,38 +372,6 @@ String AccessibilityMediaTimeline::Description(
                          : WebLocalizedString::kAXMediaAudioSliderHelp);
 }
 
-//
-// AccessibilityMediaVolumeSlider
-
-AccessibilityMediaVolumeSlider::AccessibilityMediaVolumeSlider(
-    LayoutObject* layout_object,
-    AXObjectCacheImpl& ax_object_cache)
-    : AXSlider(layout_object, ax_object_cache) {}
-
-AXObject* AccessibilityMediaVolumeSlider::Create(
-    LayoutObject* layout_object,
-    AXObjectCacheImpl& ax_object_cache) {
-  return MakeGarbageCollected<AccessibilityMediaVolumeSlider>(layout_object,
-                                                              ax_object_cache);
-}
-
-String AccessibilityMediaVolumeSlider::Description(
-    ax::mojom::NameFrom name_from,
-    ax::mojom::DescriptionFrom& description_from,
-    AXObjectVector* description_objects) const {
-  return QueryString(WebLocalizedString::kAXMediaVolumeSliderHelp);
-}
-
-bool AccessibilityMediaVolumeSlider::InternalSetAccessibilityFocusAction() {
-  MediaControlElementsHelper::NotifyMediaControlAccessibleFocus(GetElement());
-  return AXSlider::InternalSetAccessibilityFocusAction();
-}
-
-bool AccessibilityMediaVolumeSlider::InternalClearAccessibilityFocusAction() {
-  MediaControlElementsHelper::NotifyMediaControlAccessibleBlur(GetElement());
-  return AXSlider::InternalClearAccessibilityFocusAction();
-}
-
 //
 // AccessibilityMediaTimeDisplay
 

third_party/blink/renderer/modules/accessibility/ax_media_controls.h

@@ -81,24 +81,6 @@ class AccessibilityMediaTimeline final : public AXSlider {
   DISALLOW_COPY_AND_ASSIGN(AccessibilityMediaTimeline);
 };
 
-class AccessibilityMediaVolumeSlider final : public AXSlider {
- public:
-  static AXObject* Create(LayoutObject*, AXObjectCacheImpl&);
-
-  AccessibilityMediaVolumeSlider(LayoutObject*, AXObjectCacheImpl&);
-  ~AccessibilityMediaVolumeSlider() override = default;
-
-  String Description(ax::mojom::NameFrom,
-                     ax::mojom::DescriptionFrom&,
-                     AXObjectVector* description_objects) const override;
-
-  bool InternalSetAccessibilityFocusAction() override;
-  bool InternalClearAccessibilityFocusAction() override;
-
- private:
-  DISALLOW_COPY_AND_ASSIGN(AccessibilityMediaVolumeSlider);
-};
-
 class AXMediaControlsContainer final : public AccessibilityMediaControl {
  public:
   static AXObject* Create(LayoutObject*, AXObjectCacheImpl&);

third_party/blink/renderer/modules/accessibility/ax_object_cache_impl.cc

@@ -82,6 +82,7 @@
 #include "third_party/blink/renderer/modules/accessibility/ax_slider.h"
 #include "third_party/blink/renderer/modules/accessibility/ax_svg_root.h"
 #include "third_party/blink/renderer/modules/accessibility/ax_virtual_object.h"
+#include "third_party/blink/renderer/modules/media_controls/elements/media_control_elements_helper.h"
 #include "third_party/blink/renderer/modules/permissions/permission_utils.h"
 
 namespace blink {
@@ -311,8 +312,13 @@ AXObject* AXObjectCacheImpl::CreateFromRenderer(LayoutObject* layout_object) {
     return AXList::Create(layout_object, *this);
 
   // media controls
-  if (node && node->IsMediaControlElement())
+  // TODO(https://crbug.com/836549): Remove for the rest of the controls.
+  // kMediaVolumeSlider has already been removed.
+  if (node && node->IsMediaControlElement() &&
+      MediaControlElementsHelper::GetMediaControlElementType(node) !=
+          kMediaVolumeSlider) {
     return AccessibilityMediaControl::Create(layout_object, *this);
+  }
 
   if (IsHTMLOptionElement(node))
     return AXListBoxOption::Create(layout_object, *this);

third_party/blink/renderer/modules/media_controls/elements/media_control_volume_slider_element.cc

@@ -20,6 +20,9 @@ MediaControlVolumeSliderElement::MediaControlVolumeSliderElement(
     MediaControlsImpl& media_controls)
     : MediaControlSliderElement(media_controls, kMediaVolumeSlider) {
   setAttribute(html_names::kMaxAttr, "1");
+  setAttribute(html_names::kAriaValuemaxAttr, "100");
+  setAttribute(html_names::kAriaValueminAttr, "0");
+  setAttribute(html_names::kAriaLabelAttr, "volume");
   SetShadowPseudoId(AtomicString("-webkit-media-controls-volume-slider"));
   SetVolumeInternal(MediaElement().volume());
 
@@ -104,6 +107,9 @@ void MediaControlVolumeSliderElement::DefaultEventHandler(Event& event) {
 void MediaControlVolumeSliderElement::SetVolumeInternal(double volume) {
   SetupBarSegments();
   SetAfterSegmentPosition(MediaControlSliderElement::Position(0, volume));
+  int percent_vol = 100 * volume;
+  setAttribute(html_names::kAriaValuenowAttr,
+               WTF::AtomicString::Number(percent_vol));
 }
 
 bool MediaControlVolumeSliderElement::KeepEventInNode(