cc: Implement deadine scheduling disabled by default

cc/scheduler/frame_rate_controller.cc

Index: cc/scheduler/frame_rate_controller.cc
diff --git a/cc/scheduler/frame_rate_controller.cc b/cc/scheduler/frame_rate_controller.cc
index 54c1bdaf48f15d12b52d075c5ee7a30a112a0f9b..90dec25f7ef21648a44adfb7f3076e177561394c 100644
--- a/cc/scheduler/frame_rate_controller.cc
+++ b/cc/scheduler/frame_rate_controller.cc
@@ -76,9 +76,10 @@ BeginFrameArgs FrameRateController::SetActive(bool active) {
     base::TimeTicks missed_tick_time = time_source_->SetActive(active);
     if (!missed_tick_time.is_null()) {
       base::TimeTicks deadline = NextTickTime();
-      return BeginFrameArgs::Create(missed_tick_time,
-                                    deadline,
-                                    interval_);
+      BeginFrameArgs args =
+          BeginFrameArgs::Create(missed_tick_time, deadline, interval_);
+      args.deadline += deadline_adjustment_;

[danakj, 2013/09/17 20:26:19]

Is this covered by a unit test?

[brianderson, 2013/09/17 21:08:24]

There are few ways to handle the first frame's deadline with different trade
offs (faster 1st frame vs lower latency). I'm not sure I want to add a test that
forces a particular implementation.

+      return args;
     }
   } else {
     if (active)
@@ -118,10 +119,11 @@ void FrameRateController::OnTimerTick() {
   if (client_) {
     // TODO(brianderson): Use an adaptive parent compositor deadline.
     base::TimeTicks frame_time = LastTickTime();
-    base::TimeTicks deadline = NextTickTime() + deadline_adjustment_;
-    client_->FrameRateControllerTick(
-        throttled,
-        BeginFrameArgs::Create(frame_time, deadline, interval_));
+    base::TimeTicks deadline = NextTickTime();
+    BeginFrameArgs args =
+        BeginFrameArgs::Create(frame_time, deadline, interval_);
+    args.deadline += deadline_adjustment_;

[danakj, 2013/09/17 20:26:19]

why adjust the deadline after instead of just passing in the adjusted deadline?
is this a functional change? if not, the old way reads easier IMO. (same thing
up above)

[brianderson, 2013/09/17 21:08:24]

I used to have an AdjustDeadline method that would make it very obvious where
the deadlines were being modified, but decided it didn't add much value and
removed it. It doesn't make much sense to structure the code the way it is now
without that method, so I will revert to the old way.

+    client_->FrameRateControllerTick(throttled, args);
   }
 
   if (!is_time_source_throttling_ && !throttled)