cc: Introduce BeginFrame sequence numbers and acknowledgements.

cc/blimp/layer_tree_host_remote.cc

Index: cc/blimp/layer_tree_host_remote.cc
diff --git a/cc/blimp/layer_tree_host_remote.cc b/cc/blimp/layer_tree_host_remote.cc
index 466a4209370460a429f6a3f943a2e735f5de5b43..f6d1d56ed94be410642345c286ce0c1909e1c512 100644
--- a/cc/blimp/layer_tree_host_remote.cc
+++ b/cc/blimp/layer_tree_host_remote.cc
@@ -371,7 +371,9 @@ void LayerTreeHostRemote::BeginMainFrame() {
   current_pipeline_stage_ = FramePipelineStage::ANIMATE;
   base::TimeTicks now = base::TimeTicks::Now();
   client_->BeginMainFrame(BeginFrameArgs::Create(
-      BEGINFRAME_FROM_HERE, now, now + kDefaultFrameInterval,
+      BEGINFRAME_FROM_HERE,
+      static_cast<uint64_t>(reinterpret_cast<std::uintptr_t>(this)),
+      begin_frame_number_++, now, now + kDefaultFrameInterval,
       kDefaultFrameInterval, BeginFrameArgs::NORMAL));
   // We don't run any animations on the layer because threaded animations are
   // disabled.