Introduce RenderFrameObserver.

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': [
     '../jingle/jingle.gyp:jingle_glue',
     '../media/media.gyp:media',
     '../net/net.gyp:net',
     '../skia/skia.gyp:skia',
@@ skipping 30 matching lines @@
     'public/renderer/document_state.h',
     'public/renderer/history_item_serialization.cc',
     'public/renderer/history_item_serialization.h',
     'public/renderer/key_system_info.cc',
     'public/renderer/key_system_info.h',
     'public/renderer/navigation_state.cc',
     'public/renderer/navigation_state.h',
     'public/renderer/pepper_plugin_instance.h',
     'public/renderer/renderer_ppapi_host.h',
     'public/renderer/render_frame.h',
+    'public/renderer/render_frame_observer.cc',
+    'public/renderer/render_frame_observer.h',
+    'public/renderer/render_frame_observer_tracker.h',
     'public/renderer/render_process_observer.cc',
     'public/renderer/render_process_observer.h',
     'public/renderer/render_thread.cc',
     'public/renderer/render_thread.h',
     'public/renderer/render_view.h',
     'public/renderer/render_view_observer.cc',
     'public/renderer/render_view_observer.h',
     'public/renderer/render_view_observer_tracker.h',
     'public/renderer/render_view_visitor.h',
     'public/renderer/resource_fetcher.h',
@@ skipping 676 matching lines @@
     }],
   ],
   'target_conditions': [
     ['OS=="android"', {
       'sources/': [
         ['include', '^renderer/render_view_linux\\.cc$'],
       ],
     }],
   ],
 }