Splitting DidSwap in cc::SwapPromise into WillSwap and DidSwap

cc/trees/layer_tree_host_impl.cc

Index: cc/trees/layer_tree_host_impl.cc
diff --git a/cc/trees/layer_tree_host_impl.cc b/cc/trees/layer_tree_host_impl.cc
index de50e70ea351370c82a80dde3788be6b893962c6..f299ec180ed6a01dcdee0f6e4ebb39cef8ddb37a 100644
--- a/cc/trees/layer_tree_host_impl.cc
+++ b/cc/trees/layer_tree_host_impl.cc
@@ -1666,6 +1666,8 @@ bool LayerTreeHostImpl::DrawLayers(FrameData* frame) {
   compositor_frame.render_pass_list = std::move(frame->render_passes);
   compositor_frame_sink_->SubmitCompositorFrame(std::move(compositor_frame));
 
+  active_tree()->ClearSwapPromises();

[Fady Samuel, 2016/12/15 21:08:40]

Is this necessary? Why was this added?

[Saman Sami, 2016/12/15 21:20:55]

This calls DidSwap, and clears the swap promise list.

+
   // The next frame should start by assuming nothing has changed, and changes
   // are noted as they occur.
   // TODO(boliu): If we did a temporary software renderer frame, propogate the
@@ -1681,6 +1683,7 @@ bool LayerTreeHostImpl::DrawLayers(FrameData* frame) {
   benchmark_instrumentation::IssueImplThreadRenderingStatsEvent(
       rendering_stats_instrumentation_->impl_thread_rendering_stats());
   rendering_stats_instrumentation_->AccumulateAndClearImplThreadStats();
+

[Fady Samuel, 2016/12/15 21:08:40]

Remove blank line?

[Saman Sami, 2016/12/15 21:20:55]

Done.

   return true;
 }