cc/viz: Add some more trace events.

. Add a 'NeedsBeginFrames' async-event to show the duration of a
  client's request for begin-frames.
. Add a flow-event for 'did not produce' frames.
. Add a trace-event for when a client is throttled (and include
  the reason for throttling).

BUG=none

Change-Id: I65e601b54a683bef54142b98f6faf037cc22308e
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2125618
Commit-Queue: Behdad Bakhshinategh <behdadb@chromium.org>
Reviewed-by: Behdad Bakhshinategh <behdadb@chromium.org>
Auto-Submit: Sadrul Chowdhury <sadrul@chromium.org>
Cr-Commit-Position: refs/heads/master@{#754980}

cc/mojo_embedder/async_layer_tree_frame_sink.cc

@@ -252,6 +252,10 @@ void AsyncLayerTreeFrameSink::DidNotProduceFrame(
   // BeginFrames. https://crbug.com/881949
   auto it = pipeline_reporting_frame_times_.find(ack.trace_id);
   if (it != pipeline_reporting_frame_times_.end()) {
+    TRACE_EVENT_WITH_FLOW1("viz,benchmark", "Graphics.Pipeline",
+                           TRACE_ID_GLOBAL(ack.trace_id),
+                           TRACE_EVENT_FLAG_FLOW_IN | TRACE_EVENT_FLAG_FLOW_OUT,
+                           "step", "DidNotProduceFrame");
     compositor_frame_sink_ptr_->DidNotProduceFrame(ack);
     pipeline_reporting_frame_times_.erase(it);
   }
@@ -335,6 +339,13 @@ void AsyncLayerTreeFrameSink::ReclaimResources(
 
 void AsyncLayerTreeFrameSink::OnNeedsBeginFrames(bool needs_begin_frames) {
   DCHECK(compositor_frame_sink_ptr_);
+  if (needs_begin_frames_ != needs_begin_frames) {
+    if (needs_begin_frames_) {
+      TRACE_EVENT_ASYNC_END0("cc,benchmark", "NeedsBeginFrames", this);
+    } else {
+      TRACE_EVENT_ASYNC_BEGIN0("cc,benchmark", "NeedsBeginFrames", this);
+    }
+  }
   needs_begin_frames_ = needs_begin_frames;
   compositor_frame_sink_ptr_->SetNeedsBeginFrame(needs_begin_frames);
 }

components/viz/service/frame_sinks/compositor_frame_sink_support.cc

@@ -41,6 +41,7 @@ enum class SendBeginFrameResult {
 };
 
 void RecordShouldSendBeginFrame(SendBeginFrameResult result) {
+  TRACE_EVENT1("viz", "ShouldNotSendBeginFrame", "reason", result);
   UMA_HISTOGRAM_ENUMERATION(
       "Compositing.CompositorFrameSinkSupport.ShouldSendBeginFrame", result);
 }
@@ -323,9 +324,10 @@ bool CompositorFrameSinkSupport::IsRoot() const {
 }
 
 void CompositorFrameSinkSupport::DidNotProduceFrame(const BeginFrameAck& ack) {
-  TRACE_EVENT2("viz", "CompositorFrameSinkSupport::DidNotProduceFrame",
-               "ack.source_id", ack.frame_id.source_id, "ack.sequence_number",
-               ack.frame_id.sequence_number);
+  TRACE_EVENT_WITH_FLOW2(
+      "viz,benchmark", "Graphics.Pipeline", TRACE_ID_GLOBAL(ack.trace_id),
+      TRACE_EVENT_FLAG_FLOW_IN | TRACE_EVENT_FLAG_FLOW_OUT, "step",
+      "DidNotProduceFrame", "FrameSinkId", frame_sink_id_.ToString());
   DCHECK(ack.frame_id.IsSequenceValid());
 
   begin_frame_tracker_.ReceivedAck(ack);