cc: Introduce forward_begin_frames_to_children and use_external_begin_frame_source

cc/scheduler/scheduler_settings.h

 // Copyright 2013 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.
 
 #ifndef CC_SCHEDULER_SCHEDULER_SETTINGS_H_
 #define CC_SCHEDULER_SCHEDULER_SETTINGS_H_
 
 #include "base/memory/ref_counted.h"
 #include "base/values.h"
 #include "cc/base/cc_export.h"
 
 namespace base {
 namespace debug {
 class ConvertableToTraceFormat;
 }
 }
 
 namespace cc {
 class LayerTreeSettings;
 
 class CC_EXPORT SchedulerSettings {
  public:
   SchedulerSettings();
   explicit SchedulerSettings(const LayerTreeSettings& settings);
   ~SchedulerSettings();
 
-  bool begin_frame_scheduling_enabled;
+  bool begin_frame_receiver;
+  bool begin_frame_publisher;
   bool main_frame_before_activation_enabled;
   bool impl_side_painting;
   bool timeout_and_draw_when_animation_checkerboards;
   int maximum_number_of_failed_draws_before_draw_is_forced_;
   bool using_synchronous_renderer_compositor;
   bool throttle_frame_production;
   bool disable_hi_res_timer_tasks_on_battery;
 
   scoped_refptr<base::debug::ConvertableToTraceFormat> AsValue() const;
 };
 
 }  // namespace cc
 
 #endif  // CC_SCHEDULER_SCHEDULER_SETTINGS_H_