Hook up ui::Compositor to Display's BeginFrameSource

components/mus/surfaces/top_level_display_client.cc

 // Copyright 2015 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 "components/mus/surfaces/top_level_display_client.h"
 
 #include "base/thread_task_runner_handle.h"
 #include "cc/output/compositor_frame.h"
 #include "cc/output/copy_output_request.h"
 #include "cc/scheduler/begin_frame_source.h"
@@ skipping 81 matching lines @@
 
 void TopLevelDisplayClient::OutputSurfaceLost() {
   if (!display_)  // Shutdown case
     return;
   display_.reset();
 }
 
 void TopLevelDisplayClient::SetMemoryPolicy(
     const cc::ManagedMemoryPolicy& policy) {}
 
+cc::BeginFrameSource* TopLevelDisplayClient::BeginFrameSourceForChildren() {
+  return synthetic_frame_source_.get();
+}
+
 void TopLevelDisplayClient::OnVSyncParametersUpdated(int64_t timebase,
                                                      int64_t interval) {
   auto timebase_time_ticks = base::TimeTicks::FromInternalValue(timebase);
   auto interval_time_delta = base::TimeDelta::FromInternalValue(interval);
 
   if (interval_time_delta.is_zero()) {
     // TODO(brianderson): We should not be receiving 0 intervals.
     interval_time_delta = cc::BeginFrameArgs::DefaultInterval();
   }
 
   synthetic_frame_source_->OnUpdateVSyncParameters(timebase_time_ticks,
                                                    interval_time_delta);
 }
 
 void TopLevelDisplayClient::ReturnResources(
     const cc::ReturnedResourceArray& resources) {
   // TODO(fsamuel): Implement this.
 }
 
 void TopLevelDisplayClient::SetBeginFrameSource(
     cc::BeginFrameSource* begin_frame_source) {
   // TODO(tansell): Implement this.
 }
 
 }  // namespace mus