Refactoring the way begin frame sources inside scheduler work.

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': {
     'chromium_code': 1,
   },
   'targets': [
     {
@@ skipping 409 matching lines @@
         'resources/ui_resource_bitmap.cc',
         'resources/ui_resource_bitmap.h',
         'resources/ui_resource_client.h',
         'resources/ui_resource_request.cc',
         'resources/ui_resource_request.h',
         'resources/video_resource_updater.cc',
         'resources/video_resource_updater.h',
         'scheduler/delay_based_time_source.cc',
         'scheduler/delay_based_time_source.h',
         'scheduler/draw_swap_readback_result.h',
+        'scheduler/frame_source.cc',
+        'scheduler/frame_source.h',
         'scheduler/scheduler.cc',
         'scheduler/scheduler.h',
         'scheduler/scheduler_settings.cc',
         'scheduler/scheduler_settings.h',
         'scheduler/scheduler_state_machine.cc',
         'scheduler/scheduler_state_machine.h',
         'scheduler/time_source.h',
         'trees/blocking_task_runner.cc',
         'trees/blocking_task_runner.h',
         'trees/damage_tracker.cc',
@@ skipping 48 matching lines @@
         'surfaces/surface.h',
         'surfaces/surface_aggregator.cc',
         'surfaces/surface_aggregator.h',
         'surfaces/surface_manager.cc',
         'surfaces/surface_manager.h',
         'surfaces/surfaces_export.h',
       ],
     },
   ],
 }