Add flag to disable impl-side painting

cc/cc.gyp

 # 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.
 
 {
   'variables': {
     'cc_source_files': [
       'animation.cc',
       'animation.h',
       'animation_curve.cc',
@@ skipping 281 matching lines @@
       'top_controls_manager.h',
       'top_controls_manager_client.h',
       'transferable_resource.cc',
       'transferable_resource.h',
       'transform_operation.cc',
       'transform_operation.h',
       'transform_operations.cc',
       'transform_operations.h',
       'tree_synchronizer.cc',
       'tree_synchronizer.h',
+      'util.cc',
       'util.h',
       'video_frame_provider.h',
       'video_frame_provider_client_impl.cc',
       'video_frame_provider_client_impl.h',
       'video_layer.cc',
       'video_layer.h',
       'video_layer_impl.cc',
       'video_layer_impl.h',
       'vsync_time_source.cc',
       'vsync_time_source.h',
@@ skipping 40 matching lines @@
         'include_dirs': [
           # TODO(jamesr): Remove once https://webkit.org/b/105259 lands + rolls
           '<(webkit_src_dir)/Source/Platform/chromium'
         ]
       },
       # TODO(jschuh): crbug.com/167187 fix size_t to int truncations.
       'msvs_disabled_warnings': [ 4267, ],
     },
   ],
 }