Add ChromeVox panel and implement caption display functionality.

chrome/browser/resources/chromeos/chromevox/chromevox_assets.gypi

 # Copyright 2014 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 {
   'variables': {
-    'chromevox_assets_chromevox': [
-      'chromevox/chromevox-128.png',
-      'chromevox/chromevox-16.png',
-      'chromevox/chromevox-19.png',
-      'chromevox/chromevox-48.png',
+    'chromevox_assets_images': [
+      'images/chromevox-128.png',
+      'images/chromevox-16.png',
+      'images/chromevox-19.png',
+      'images/chromevox-48.png',
+      'images/close-19.png',
+      'images/close-hover-19.png',
+      'images/options-19.png',
+      'images/options-hover-19.png',
+      'images/triangle-6.png',
     ],
     'chromevox_assets_chromevox_background_earcons': [
       'chromevox/background/earcons/alert_modal.ogg',
       'chromevox/background/earcons/alert_nonmodal.ogg',
       'chromevox/background/earcons/button.ogg',
       'chromevox/background/earcons/check_off.ogg',
       'chromevox/background/earcons/check_on.ogg',
       'chromevox/background/earcons/editable_text.ogg',
       'chromevox/background/earcons/invalid_keypress.ogg',
       'chromevox/background/earcons/link.ogg',
@@ skipping 63 matching lines @@
       'cvox2/background/earcons/small_room_2.wav',
       'cvox2/background/earcons/static.wav',
     ],
   },
   'targets': [
     {
       'target_name': 'chromevox_assets',
       'type': 'none',
       'copies': [
         {
-          'destination': '<(chromevox_dest_dir)/chromevox',
+          'destination': '<(chromevox_dest_dir)/images',
           'files': [
-            '<@(chromevox_assets_chromevox)',
+            '<@(chromevox_assets_images)',
           ],
         },
         {
           'destination': '<(chromevox_dest_dir)/chromevox/background/earcons',
           'files': [
             '<@(chromevox_assets_chromevox_background_earcons)',
           ],
         },
         {
           'destination': '<(chromevox_dest_dir)/chromevox/background/keymaps',
@@ skipping 16 matching lines @@
         {
           'destination': '<(chromevox_dest_dir)/cvox2/background/earcons',
           'files': [
             '<@(chromevox_assets_cvox2_background_earcons)',
           ],
         },
       ],
     },
   ],
 }