Decouple BrowserCompositorOutputSurface from BeginFrameSource.

ui/compositor/compositor_vsync_manager.cc

 // Copyright 2014 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.
 
 #include "ui/compositor/compositor_vsync_manager.h"
 
 namespace ui {
 
 CompositorVSyncManager::CompositorVSyncManager()
     : authoritative_vsync_interval_(base::TimeDelta::FromSeconds(0)) {
@@ skipping 10 matching lines @@
 
 void CompositorVSyncManager::UpdateVSyncParameters(base::TimeTicks timebase,
                                                    base::TimeDelta interval) {
   if (authoritative_vsync_interval_ != base::TimeDelta::FromSeconds(0))
     interval = authoritative_vsync_interval_;
   last_timebase_ = timebase;
   last_interval_ = interval;
   NotifyObservers(timebase, interval);
 }
 
-void CompositorVSyncManager::AddObserver(Observer* observer) {
+void CompositorVSyncManager::AddObserver(cc::VSyncObserver* observer) {
   observer_list_.AddObserver(observer);
   observer->OnUpdateVSyncParameters(last_timebase_, last_interval_);
 }
 
-void CompositorVSyncManager::RemoveObserver(Observer* observer) {
+void CompositorVSyncManager::RemoveObserver(cc::VSyncObserver* observer) {
   observer_list_.RemoveObserver(observer);
 }
 
 void CompositorVSyncManager::NotifyObservers(base::TimeTicks timebase,
                                              base::TimeDelta interval) {
   for (auto& observer : observer_list_)
     observer.OnUpdateVSyncParameters(timebase, interval);
 }
 
 }  // namespace ui