Refactor content/renderer/accessibility to use AXTreeSerializer (re-land).

content/content_renderer.gypi

 # Copyright (c) 2012 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.
 
 {
   'dependencies': [
     '../gin/gin.gyp:gin',
     '../jingle/jingle.gyp:jingle_glue',
     '../media/media.gyp:media',
     '../net/net.gyp:net',
@@ skipping 51 matching lines @@
     'public/renderer/render_view_visitor.h',
     'public/renderer/resource_fetcher.h',
     'public/renderer/v8_value_converter.h',
     'public/renderer/video_encode_accelerator.cc',
     'public/renderer/video_encode_accelerator.h',
     'public/renderer/web_preferences.h',
     'renderer/accessibility/accessibility_node_serializer.cc',
     'renderer/accessibility/accessibility_node_serializer.h',
     'renderer/accessibility/blink_ax_enum_conversion.cc',
     'renderer/accessibility/blink_ax_enum_conversion.h',
+    'renderer/accessibility/blink_ax_tree_source.cc',
+    'renderer/accessibility/blink_ax_tree_source.h',
     'renderer/accessibility/renderer_accessibility.cc',
     'renderer/accessibility/renderer_accessibility.h',
     'renderer/accessibility/renderer_accessibility_complete.cc',
     'renderer/accessibility/renderer_accessibility_complete.h',
     'renderer/accessibility/renderer_accessibility_focus_only.cc',
     'renderer/accessibility/renderer_accessibility_focus_only.h',
     'renderer/active_notification_tracker.cc',
     'renderer/active_notification_tracker.h',
     'renderer/android/address_detector.cc',
     'renderer/android/address_detector.h',
@@ skipping 687 matching lines @@
     }],
   ],
   'target_conditions': [
     ['OS=="android"', {
       'sources/': [
         ['include', '^renderer/render_view_linux\\.cc$'],
       ],
     }],
   ],
 }