blink: Fix begin-frame traces for video.

The BeginFrameAck needs to carry the trace-id from the BeginFrameArgs.
So update the code to use the ctor for BeginFrameAcks that copies over
all the necessary info from the associated BeginFrameArgs.

BUG=none

Cq-Include-Trybots: luci.chromium.try:linux_layout_tests_slimming_paint_v2;master.tryserver.blink:linux_trusty_blink_rel
Change-Id: I6b864e94cd1b7c6819f2fb1aeb35eef73bd5d253
Reviewed-on: https://chromium-review.googlesource.com/1196845Reviewed-by: Saman Sami <samans@chromium.org>
Reviewed-by: Robert Flack <flackr@chromium.org>
Commit-Queue: Sadrul Chowdhury <sadrul@chromium.org>
Cr-Commit-Position: refs/heads/master@{#589090}

third_party/blink/renderer/platform/graphics/begin_frame_provider.cc

@@ -106,11 +106,7 @@ void BeginFrameProvider::OnBeginFrame(const viz::BeginFrameArgs& args) {
     }
   }
 
-  viz::BeginFrameAck ack;
-  ack.source_id = args.source_id;
-  ack.sequence_number = args.sequence_number;
-  ack.has_damage = false;
-  compositor_frame_sink_->DidNotProduceFrame(ack);
+  compositor_frame_sink_->DidNotProduceFrame(viz::BeginFrameAck(args, false));
 }
 
 }  // namespace blink

third_party/blink/renderer/platform/graphics/video_frame_submitter.cc

@@ -304,8 +304,7 @@ void VideoFrameSubmitter::SubmitEmptyFrame() {
 void VideoFrameSubmitter::OnBeginFrame(const viz::BeginFrameArgs& args) {
   TRACE_EVENT0("media", "VideoFrameSubmitter::OnBeginFrame");
   DCHECK_CALLED_ON_VALID_THREAD(media_thread_checker_);
-  viz::BeginFrameAck current_begin_frame_ack =
-      viz::BeginFrameAck(args.source_id, args.sequence_number, false);
+  viz::BeginFrameAck current_begin_frame_ack(args, false);
   if (args.type == viz::BeginFrameArgs::MISSED) {
     compositor_frame_sink_->DidNotProduceFrame(current_begin_frame_ack);
     return;