Media Controls a11y: add text/description/role to more controls components.

content/app/strings/content_strings.grd

 <?xml version="1.0" encoding="UTF-8"?>
 
 <!-- This file contains definitions of resources that will be translated for
 each locale. Specifically, these are UI strings that are used by content that
 need to be translated for each locale.-->
 
 <!-- Some of these strings and string descriptions were taken from
 WebKit/win/WebCoreLocalizedStrings.cpp so we include the original license
 below:
 
@@ skipping 602 matching lines @@
       </message>
 
       <message name="IDS_AX_MEDIA_CAST_OFF_BUTTON" desc="accessibility role description for remote playback button">
         play on remote device
       </message>
 
       <message name="IDS_AX_MEDIA_CAST_ON_BUTTON" desc="accessibility role description for remote playback control button">
         control remote playback
       </message>
 
+      <message name="IDS_AX_MEDIA_DOWNLOAD_BUTTON" desc="Media controls download button.">
+        download media
+      </message>
+
+      <message name="IDS_AX_MEDIA_OVERFLOW_BUTTON" desc="Media controls overflow button.">
+        show more media controls
+      </message>
+
       <message name="IDS_AX_MEDIA_AUDIO_ELEMENT_HELP" desc="Accessible help of audio controls">
         audio
       </message>
 
       <message name="IDS_AX_MEDIA_VIDEO_ELEMENT_HELP" desc="Accessible help of video">
         video
       </message>
 
       <message name="IDS_AX_MEDIA_MUTE_BUTTON_HELP" desc="accessibility help description for mute button">
         mute audio track
@@ skipping 52 matching lines @@
       </message>
 
       <message name="IDS_AX_MEDIA_CAST_OFF_BUTTON_HELP" desc="accessibility help description for remote playback button">
         play on remote device
       </message>
 
       <message name="IDS_AX_MEDIA_CAST_ON_BUTTON_HELP" desc="accessibility help description for remote playback control button">
         control remote playback
       </message>
 
+      <message name="IDS_AX_MEDIA_OVERFLOW_BUTTON_HELP" desc="accessibility help description for overflow button.">
+        more options
+      </message>
+
       <message name="IDS_AX_MILLISECOND_FIELD_TEXT" desc="Accessible description of the millisecond field in a date/time control">
         Milliseconds
       </message>
 
       <message name="IDS_AX_MINUTE_FIELD_TEXT" desc="Accessible description of the minute field in a date/time control">
         Minutes
       </message>
 
       <message name="IDS_AX_MONTH_FIELD_TEXT" desc="Accessible description of the month field in a date/time control">
         Month
@@ skipping 140 matching lines @@
       <message name="IDS_FORM_VALIDATION_STEP_MISMATCH_CLOSE_TO_LIMIT" desc="Heading or short sentence shown when a form control value in a webpage should be aligned to a step value specified by the page author, but a user speficified non-aligned value. e.g. A number type field, minimum value is 0, and step value is 4. If A user-specified value is not a multiple of 4, this warning message is shown.">
         Please enter a valid value. The nearest valid value is <ph name="VALID_VALUE">$1<ex>0</ex></ph>.
       </message>
       <message name="IDS_FORM_VALIDATION_TOO_LONG" desc="Heading or short sentence shown when a form control in a webpage needs to be shorter than a length specified by the page author, but a user specified long value.">
         Please shorten this text to <ph name="MAX_CHARACTERS">$2<ex>100</ex></ph> characters or less (you are currently using <ph name="CURRENT_LENGTH">$1<ex>101</ex></ph> characters).
       </message>
       <message name="IDS_FORM_VALIDATION_TOO_SHORT" desc="Heading or short sentence shown when a form control in a webpage needs to be longer than a length specified by the page author, but a user specified short value.">
         Please lengthen this text to <ph name="MIN_CHARACTERS">$2<ex>101</ex></ph> characters or more (you are currently using <ph name="CURRENT_LENGTH">$1<ex>100</ex></ph> characters).
       </message>
 
-      <message name="IDS_AX_MEDIA_OVERFLOW_BUTTON" desc="Media controls overflow menu.">
-        Overflow menu
-      </message>
       <message name="IDS_MEDIA_OVERFLOW_MENU_CLOSED_CAPTIONS" desc="Media controls overflow menu item label for a closed captions button. The text for this overflow menu should be short.">
         Captions
       </message>
       <message name="IDS_MEDIA_OVERFLOW_MENU_CAST" desc="Media controls overflow menu item label for a cast button.">
         Cast
       </message>
       <message name="IDS_MEDIA_OVERFLOW_MENU_ENTER_FULLSCREEN" desc="Media controls overflow menu item label for a button to enter fullscreen.">
         Fullscreen
       </message>
       <message name="IDS_MEDIA_OVERFLOW_MENU_EXIT_FULLSCREEN" desc="Media controls overflow menu item label for a button to exit fullscreen.">
@@ skipping 25 matching lines @@
         Off
       </message>
 
       <message name="IDS_PLUGIN_INITIALIZATION_ERROR" desc="A message displayed when a plugin failed to load">
         Couldn't load plugin.
       </message>
 
     </messages>
   </release>
 </grit>