Plumb activation time to main

cc/scheduler/scheduler.cc

Index: cc/scheduler/scheduler.cc
diff --git a/cc/scheduler/scheduler.cc b/cc/scheduler/scheduler.cc
index 8b13d94c5ba40a9116026dc85d2a5bdfc5b766e6..c24966ae2d9b02bb8f7a46514f065fba60dc942f 100644
--- a/cc/scheduler/scheduler.cc
+++ b/cc/scheduler/scheduler.cc
@@ -82,9 +82,18 @@ void Scheduler::SetCanDraw(bool can_draw) {
   ProcessScheduledActions();
 }
 
-void Scheduler::NotifyReadyToActivate() {
+void Scheduler::NotifyReadyToActivate(int source_frame_number) {
   compositor_timing_history_->ReadyToActivate();
   state_machine_.NotifyReadyToActivate();
+  if (source_frame_number != -1) {
+    if (ready_to_activate_time_.empty() ||
+        ready_to_activate_time_.back().first !=
+            static_cast<unsigned>(source_frame_number)) {
+      // Note the activate source-frame and timestamp
+      ready_to_activate_time_.emplace_back(source_frame_number,
+                                           base::TimeTicks::Now());
+    }
+  }
   ProcessScheduledActions();
 }
 
@@ -607,7 +616,6 @@ void Scheduler::ProcessScheduledActions() {
   // The top-level call will iteratively execute the next action for us anyway.
   if (inside_process_scheduled_actions_)
     return;
-
   base::AutoReset<bool> mark_inside(&inside_process_scheduled_actions_, true);
 
   SchedulerStateMachine::Action action;
@@ -626,6 +634,9 @@ void Scheduler::ProcessScheduledActions() {
             begin_main_frame_args_.frame_time);
         state_machine_.WillSendBeginMainFrame();
         // TODO(brianderson): Pass begin_main_frame_args_ directly to client.
+        begin_main_frame_args_.ready_to_activate_time =
+            std::move(ready_to_activate_time_);
+        ready_to_activate_time_.clear();
         client_->ScheduledActionSendBeginMainFrame(begin_main_frame_args_);
         break;
       case SchedulerStateMachine::ACTION_COMMIT: {