cc: Record frame timing composite events in the tracker.

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 d89bad30481ac47b8f9aaf27ccbaa723e278c452..c9241a3d271256a6b33eeab0de844b582510d5ae 100644
--- a/cc/trees/layer_tree_host_impl.cc
+++ b/cc/trees/layer_tree_host_impl.cc
@@ -229,7 +229,8 @@ LayerTreeHostImpl::LayerTreeHostImpl(
       gpu_memory_buffer_manager_(gpu_memory_buffer_manager),
       id_(id),
       requires_high_res_to_draw_(false),
-      required_for_draw_tile_is_top_of_raster_queue_(false) {
+      required_for_draw_tile_is_top_of_raster_queue_(false),
+      frame_timing_tracker_(FrameTimingTracker::Create()) {
   DCHECK(proxy_->IsImplThread());
   DidVisibilityChange(this, visible_);
   animation_registrar_->set_supports_scroll_animations(
@@ -801,6 +802,18 @@ DrawResult LayerTreeHostImpl::CalculateRenderPasses(
                             *it,
                             occlusion_tracker,
                             &append_quads_data);
+
+        // For layers that represent themselves, add composite frame timing
+        // requests if the visible rect intersects the requested rect.
+        const std::vector<FrameTimingRequest>& frame_timing_requests =
+            it->frame_timing_requests();
+        for (const auto& request : frame_timing_requests) {

[danakj, 2015/02/02 21:19:06]

you could just : it->frame_timing_requests())  ? and avoid the temp var?

[vmpstr, 2015/02/02 22:32:05]

Done.

+          if (request.rect().Intersects(it->visible_content_rect())) {

[danakj, 2015/02/02 21:19:06]

you need to map this VCR to layer space

[vmpstr, 2015/02/02 22:32:05]

Done.

+            current_composite_events_.push_back(
+                FrameTimingTracker::FrameAndRectIds(
+                    active_tree_->source_frame_number(), request.id()));
+          }
+        }
       }
 
       ++layers_drawn;
@@ -1049,6 +1062,7 @@ DrawResult LayerTreeHostImpl::PrepareToDraw(FrameData* frame) {
   if (draw_result != DRAW_SUCCESS) {
     DCHECK(!output_surface_->capabilities()
                .draw_and_swap_full_viewport_every_frame);
+    current_composite_events_.clear();

[danakj, 2015/02/02 21:19:06]

if you make this a member of the |frame| then you don't have to worry about
clearing it after each frame?

[vmpstr, 2015/02/02 22:32:05]

Done.

     return draw_result;
   }
 
@@ -1437,6 +1451,12 @@ void LayerTreeHostImpl::DrawLayers(FrameData* frame,
   TRACE_EVENT0("cc", "LayerTreeHostImpl::DrawLayers");
   DCHECK(CanDraw());
 
+  if (!current_composite_events_.empty()) {
+    frame_timing_tracker_->SaveTimeStamps(base::TimeTicks::Now(),

[danakj, 2015/02/02 21:19:06]

should we use the frame time instead of now?

[vmpstr, 2015/02/02 22:32:05]

Done. I think that works. According to the spec, we want the "time of the
event", the event being the composite event, which I think the impl frame time
captures.

+                                          current_composite_events_);
+    current_composite_events_.clear();
+  }
+
   if (frame->has_no_damage) {
     TRACE_EVENT_INSTANT0("cc", "EarlyOut_NoDamage", TRACE_EVENT_SCOPE_THREAD);
     DCHECK(!output_surface_->capabilities()