cc: Introduce BeginFrame sequence numbers and acknowledgements.

cc/trees/single_thread_proxy.cc

Index: cc/trees/single_thread_proxy.cc
diff --git a/cc/trees/single_thread_proxy.cc b/cc/trees/single_thread_proxy.cc
index 593a7dc06294fd091f695cb336767deee46edc6a..fbb1aae14fb0bacdc4fd00d3c586638aa9897530 100644
--- a/cc/trees/single_thread_proxy.cc
+++ b/cc/trees/single_thread_proxy.cc
@@ -450,7 +450,7 @@ void SingleThreadProxy::CompositeImmediately(base::TimeTicks frame_begin_time) {
   }
 
   BeginFrameArgs begin_frame_args(BeginFrameArgs::Create(
-      BEGINFRAME_FROM_HERE, frame_begin_time, base::TimeTicks(),
+      BEGINFRAME_FROM_HERE, 0, 0, frame_begin_time, base::TimeTicks(),
       BeginFrameArgs::DefaultInterval(), BeginFrameArgs::NORMAL));
 
   // Start the impl frame.
@@ -692,6 +692,12 @@ void SingleThreadProxy::BeginMainFrameAbortedOnImplThread(
 DrawResult SingleThreadProxy::ScheduledActionDrawIfPossible() {
   DebugScopedSetImplThread impl(task_runner_provider_);
   LayerTreeHostImpl::FrameData frame;
+  frame.begin_frame_source_id =
+      scheduler_on_impl_thread_->CurrentBeginFrameSourceId();
+  frame.begin_frame_number =
+      scheduler_on_impl_thread_->CurrentBeginFrameNumber();
+  frame.oldest_incorporated_frame =
+      scheduler_on_impl_thread_->OldestIncorporatedFrameForActiveTree();
   return DoComposite(&frame);
 }