Fix support for accessible action verbs and performing the default action.

content/app/strings/content_strings.grd

Index: content/app/strings/content_strings.grd
diff --git a/content/app/strings/content_strings.grd b/content/app/strings/content_strings.grd
index 452730f5e578653dd2ae90932af5e0ee4675d572..51f16efe0cafd77a093805fcce3404e991a5ffc9 100644
--- a/content/app/strings/content_strings.grd
+++ b/content/app/strings/content_strings.grd
@@ -526,6 +526,12 @@ below:
       <message name="IDS_AX_LINK_ACTION_VERB" desc="Verb stating the action that will occur when a link is clicked, as used by accessibility.">
         jump
       </message>
+      <message name="IDS_AX_POP_UP_BUTTON_ACTION_VERB" desc="Verb stating the action that will occur when a pop-up button is clicked, as used by accessibility.">
+        open
+      </message>
+      <message name="IDS_AX_DEFAULT_ACTION_VERB" desc="Verb stating the action that will occur when clicking on a generic clickable object, when we don't know what that action is, as used by accessibility.">
+        click
+      </message>
 
       <message name="IDS_AX_AM_PM_FIELD_TEXT" desc="Accessible description of the AM/PM field in a date/time control">
         AM/PM
@@ -606,11 +612,11 @@ below:
       <message name="IDS_AX_MEDIA_HIDE_CLOSED_CAPTIONS_BUTTON" desc="accessibility role description for hide closed captions button">
         hide closed captions
       </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>
@@ -682,7 +688,7 @@ below:
       <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>