cc: Add main frame timing info to frame timing 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 86401a7dca992c469fca2e80606a9aeac99ff513..95ec1a677b9a3d87ea935d4276550374ef23f524 100644
--- a/cc/trees/layer_tree_host_impl.cc
+++ b/cc/trees/layer_tree_host_impl.cc
@@ -305,6 +305,11 @@ void LayerTreeHostImpl::CommitComplete() {
 
   sync_tree()->set_needs_update_draw_properties();
 
+  // If we don't have a pending tree, it means we've committed directly to the
+  // active tree. In that case, record frame timing information immediately.
+  if (!pending_tree_)
+    RecordMainFrameTiming();
+
   if (settings_.impl_side_painting) {
     // Impl-side painting needs an update immediately post-commit to have the
     // opportunity to create tilings.  Other paths can call UpdateDrawProperties
@@ -1800,6 +1805,10 @@ void LayerTreeHostImpl::ActivateSyncTree() {
         root_layer_scroll_offset_delegate_);
 
     UpdateViewportContainerSizes();
+
+    // If we had a pending tree, now is when we should record main frame timing
+    // information.
+    RecordMainFrameTiming();
   } else {
     active_tree_->ProcessUIResourceRequestQueue();
   }
@@ -2074,6 +2083,23 @@ void LayerTreeHostImpl::CreateResourceAndTileTaskWorkerPool(
                                      settings_.renderer_settings.refresh_rate));
 }
 
+void LayerTreeHostImpl::SetBeginMainFrameTime(base::TimeTicks frame_time) {
+  main_frame_time_ = frame_time;
+}
+
+void LayerTreeHostImpl::RecordMainFrameTiming() {
+  std::vector<int64_t> request_ids;
+  active_tree_->GatherFrameTimingRequestIds(&request_ids);
+  if (request_ids.empty())
+    return;
+
+  base::TimeDelta frame_duration =
+      client_->GetNextBeginImplFrameTimeIfRequested() - main_frame_time_;
+  frame_timing_tracker_->SaveMainFrameTimeStamps(
+      request_ids, main_frame_time_, frame_duration,
+      active_tree_->source_frame_number());
+}
+
 void LayerTreeHostImpl::DestroyTileManager() {
   tile_manager_ = nullptr;
   resource_pool_ = nullptr;