media_controls: Add UI for showing a promo bubble on a control button.

third_party/WebKit/Source/modules/accessibility/AXMediaControls.cpp

Index: third_party/WebKit/Source/modules/accessibility/AXMediaControls.cpp
diff --git a/third_party/WebKit/Source/modules/accessibility/AXMediaControls.cpp b/third_party/WebKit/Source/modules/accessibility/AXMediaControls.cpp
index 70c0bad4de7fd09e583186fe99ea6131cf4a4577..73f4633f21a76e88dd04abbf6b1c35b59920d617 100644
--- a/third_party/WebKit/Source/modules/accessibility/AXMediaControls.cpp
+++ b/third_party/WebKit/Source/modules/accessibility/AXMediaControls.cpp
@@ -86,6 +86,11 @@ AXObjectImpl* AccessibilityMediaControl::Create(
     case kMediaOverflowButton:
     case kMediaOverflowList:
     case kMediaDownloadButton:
+    case kMediaDownloadButtonContainer:
+    case kMediaButtonPromoContainer:
+    case kMediaButtonPromoAnimation:
+    case kMediaButtonPromoArrow:
+    case kMediaDownloadButtonPromoText:
       return new AccessibilityMediaControl(layout_object, ax_object_cache);
   }
 
@@ -137,6 +142,8 @@ String AccessibilityMediaControl::TextAlternative(
       return QueryString(WebLocalizedString::kAXMediaCastOnButton);
     case kMediaDownloadButton:
       return QueryString(WebLocalizedString::kAXMediaDownloadButton);
+    case kMediaDownloadButtonPromoText:
+      return QueryString(WebLocalizedString::kDownloadButtonPromoText);
     case kMediaOverflowButton:
       return QueryString(WebLocalizedString::kAXMediaOverflowButton);
     case kMediaSliderThumb:
@@ -148,7 +155,10 @@ String AccessibilityMediaControl::TextAlternative(
     case kMediaVolumeSlider:
     case kMediaVolumeSliderThumb:
     case kMediaOverflowList:
-      return QueryString(WebLocalizedString::kAXMediaDefault);
+    case kMediaDownloadButtonContainer:
+    case kMediaButtonPromoContainer:
+    case kMediaButtonPromoAnimation:
+    case kMediaButtonPromoArrow:
     case kMediaSlider:
       NOTREACHED();
       return QueryString(WebLocalizedString::kAXMediaDefault);
@@ -204,6 +214,11 @@ String AccessibilityMediaControl::Description(
     case kMediaVolumeSliderThumb:
     case kMediaOverflowList:
     case kMediaDownloadButton:
+    case kMediaDownloadButtonContainer:
+    case kMediaButtonPromoContainer:
+    case kMediaButtonPromoAnimation:
+    case kMediaButtonPromoArrow:
+    case kMediaDownloadButtonPromoText:
       return QueryString(WebLocalizedString::kAXMediaDefault);
     case kMediaSlider:
       NOTREACHED();
@@ -256,6 +271,11 @@ AccessibilityRole AccessibilityMediaControl::RoleValue() const {
     case kMediaTrackSelectionCheckmark:
     case kMediaVolumeSlider:
     case kMediaVolumeSliderThumb:
+    case kMediaDownloadButtonContainer:
+    case kMediaButtonPromoContainer:
+    case kMediaButtonPromoAnimation:
+    case kMediaButtonPromoArrow:
+    case kMediaDownloadButtonPromoText:
       return kUnknownRole;
 
     case kMediaSlider: