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 d532ce3b07d7478d7eea238f0df43884f7d299e5..767802651b94b05c019cf4561ba8726e30997452 100644
--- a/cc/scheduler/scheduler.cc
+++ b/cc/scheduler/scheduler.cc
@@ -89,9 +89,14 @@ void Scheduler::SetCanDraw(bool can_draw) {
   ProcessScheduledActions();
 }
 
-void Scheduler::NotifyReadyToActivate() {
+void Scheduler::NotifyReadyToActivate(int source_frame_number) {
   compositor_timing_history_->ReadyToActivate();
   state_machine_.NotifyReadyToActivate();
+  // Note the activate source-frame and timestamp
+  if (source_frame_number != 0) {
+    ready_to_activate_time_.emplace_back(source_frame_number,
+                                         base::TimeTicks::Now());
+  }
   ProcessScheduledActions();
 }
 
@@ -608,7 +613,6 @@ 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;
@@ -627,6 +631,9 @@ 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: {