cc: Create ProxyBeginFrameSource

cc/scheduler/scheduler.cc

Index: cc/scheduler/scheduler.cc
diff --git a/cc/scheduler/scheduler.cc b/cc/scheduler/scheduler.cc
index b92b8a515b705c4a55ef5cb13a5e5479c03ec3d7..bc79776b83b4dbf1cdb1f56b833bb47e2bac6c17 100644
--- a/cc/scheduler/scheduler.cc
+++ b/cc/scheduler/scheduler.cc
@@ -80,6 +80,7 @@ Scheduler::Scheduler(
     const scoped_refptr<base::SingleThreadTaskRunner>& task_runner,
     base::PowerMonitor* power_monitor,
     scoped_ptr<BeginFrameSource> external_begin_frame_source,
+    ProxyBeginFrameSource* proxy_begin_frame_source,
     SchedulerFrameSourcesConstructor* frame_sources_constructor)
     : frame_source_(),
       primary_frame_source_(NULL),
@@ -96,6 +97,7 @@ Scheduler::Scheduler(
       state_machine_(scheduler_settings),
       inside_process_scheduled_actions_(false),
       inside_action_(SchedulerStateMachine::ACTION_NONE),
+      proxy_begin_frame_source_(proxy_begin_frame_source),
       weak_factory_(this) {
   TRACE_EVENT1(TRACE_DISABLED_BY_DEFAULT("cc.debug.scheduler"),
                "Scheduler::Scheduler",
@@ -104,6 +106,11 @@ Scheduler::Scheduler(
   DCHECK(client_);
   DCHECK(!state_machine_.BeginFrameNeeded());
 
+  if (settings_.forward_begin_frames_to_children) {
+    DCHECK(proxy_begin_frame_source_);
+    proxy_begin_frame_source_->set_delegate(this);
+  }
+
   begin_retro_frame_closure_ =
       base::Bind(&Scheduler::BeginRetroFrame, weak_factory_.GetWeakPtr());
   begin_impl_frame_deadline_closure_ = base::Bind(
@@ -139,6 +146,9 @@ Scheduler::~Scheduler() {
   TeardownPowerMonitoring();
   if (frame_source_->NeedsBeginFrames())
     frame_source_->SetNeedsBeginFrames(false);
+
+  if (proxy_begin_frame_source_)
+    proxy_begin_frame_source_->set_delegate(nullptr);
 }
 
 base::TimeTicks Scheduler::Now() const {
@@ -413,7 +423,7 @@ bool Scheduler::OnBeginFrameMixInDelegate(const BeginFrameArgs& args) {
         (client_->BeginMainFrameToCommitDurationEstimate() +
          client_->CommitToActivateDurationEstimate() +
          client_->DrawDurationEstimate() + EstimatedParentDrawTime());
-    client_->SendBeginFramesToChildren(adjusted_args_for_children);
+    proxy_begin_frame_source_->BeginFrames(adjusted_args_for_children);
   }
 
   // We have just called SetNeedsBeginFrame(true) and the BeginFrameSource has