QuickView: Add labels and tabindex for accessibility.

chrome/app/chromeos_strings.grdp

 <?xml version="1.0" encoding="utf-8"?>
 <!-- ChromeOS-specific strings (included from generated_resources.grd).
      Everything in this file is wrapped in <if expr="chromeos">. -->
 <grit-part>
   <message name="IDS_EMPTY_STRING" desc="Empty string, exist only to make code generic. No translation required.">
   </message>
   <!-- Idle logout dialog for retail mode -->
   <message name="IDS_IDLE_LOGOUT_TITLE" desc="Dialog title for the idle logout dialog. Used in retail mode only.">
     Are you still there?
   </message>
@@ skipping 208 matching lines @@
   </message>
   <message name="IDS_FILE_BROWSER_NEW_WINDOW_BUTTON_LABEL" desc="Label on the 'New window' button.">
     New window
   </message>
   <message name="IDS_FILE_BROWSER_FILENAME_LABEL" desc="Filename text area label.">
     File name
   </message>
   <message name="IDS_FILE_BROWSER_PREPARING_LABEL" desc="Label informing about preparing the file.">
     Preparing
   </message>
+  <message name="IDS_FILE_BROWSER_QUICK_VIEW_OPEN_IN_NEW_BUTTON_LABEL" desc="Label for button to open a file with external app.">
+    Open
+  </message>
+  <message name="IDS_FILE_BROWSER_QUICK_VIEW_TOGGLE_METADATA_BOX_BUTTON_LABEL" desc="Label for button to toggle show/hide status of metadata box.">
+    File info
+  </message>
   <message name="IDS_FILE_BROWSER_DRAGGING_MULTIPLE_ITEMS" desc="Tooltip message for dragging multiple files.">
     $1 items
   </message>
 
   <message name="IDS_FILE_BROWSER_ARCHIVE_MOUNT_FAILED" desc="Title of the error dialog when file mount operation failed.">
     Unable to open "$1": $2
   </message>
   <message name="IDS_FILE_BROWSER_UNMOUNT_FAILED" desc="Title of the error dialog when device unmount operation failed.">
    <ph name="BEGIN_BOLD">&lt;b&gt;</ph>Don't remove your device just yet!<ph name="END_BOLD">&lt;/b&gt;</ph>
    <ph name="LINE_BREAKS">&lt;br/&gt;&lt;br/&gt;</ph>
@@ skipping 6511 matching lines @@
   <message name="IDS_CRITICALLY_LOW_DISK_NOTIFICATION_TITLE" desc="Title of the notification warning users that they are critically low on disk space.">
     Device disk space critically low
   </message>
   <message name="IDS_CRITICALLY_LOW_DISK_NOTIFICATION_MESSAGE" desc="Notification text warning users that they are critically low on disk space.">
     Free up disk space or device will become unresponsive.
   </message>
   <message name="IDS_LOW_DISK_NOTIFICATION_BUTTON" desc="Button on the low disk notification to open storage management.">
     Manage storage
   </message>
 </grit-part>