Pipe impl_latency_takes_priority_ to the RenderScheduler.

cc/output/begin_frame_args.cc

Index: cc/output/begin_frame_args.cc
diff --git a/cc/output/begin_frame_args.cc b/cc/output/begin_frame_args.cc
index 4b43d94afe59c4388d2fb75a16478906faf50f78..8b1a12a8b9bd19faddfea0a0f6181eaf3a8d664a 100644
--- a/cc/output/begin_frame_args.cc
+++ b/cc/output/begin_frame_args.cc
@@ -27,30 +27,35 @@ BeginFrameArgs::BeginFrameArgs()
     : frame_time(base::TimeTicks()),
       deadline(base::TimeTicks()),
       interval(base::TimeDelta::FromMicroseconds(-1)),
-      type(BeginFrameArgs::INVALID) {
+      type(BeginFrameArgs::INVALID),
+      on_critical_path(false) {

[Sami, 2015/06/08 11:47:53]

I'm wondering if we should default this to true and then have a setter that can
be used to override it? Usually BeginFrames are urgent.

[alex clarke (OOO till 29th), 2015/06/08 16:58:07]

Done.

 }
 
 BeginFrameArgs::BeginFrameArgs(base::TimeTicks frame_time,
                                base::TimeTicks deadline,
                                base::TimeDelta interval,
-                               BeginFrameArgs::BeginFrameArgsType type)
+                               BeginFrameArgs::BeginFrameArgsType type,
+                               bool on_critical_path)
     : frame_time(frame_time),
       deadline(deadline),
       interval(interval),
-      type(type) {
+      type(type),
+      on_critical_path(on_critical_path) {
 }
 
 BeginFrameArgs BeginFrameArgs::Create(BeginFrameArgs::CreationLocation location,
                                       base::TimeTicks frame_time,
                                       base::TimeTicks deadline,
                                       base::TimeDelta interval,
-                                      BeginFrameArgs::BeginFrameArgsType type) {
+                                      BeginFrameArgs::BeginFrameArgsType type,
+                                      bool on_critical_path) {
   DCHECK_NE(type, BeginFrameArgs::INVALID);
   DCHECK_NE(type, BeginFrameArgs::BEGIN_FRAME_ARGS_TYPE_MAX);
 #ifdef NDEBUG
-  return BeginFrameArgs(frame_time, deadline, interval, type);
+  return BeginFrameArgs(frame_time, deadline, interval, type, on_critical_path);
 #else
-  BeginFrameArgs args = BeginFrameArgs(frame_time, deadline, interval, type);
+  BeginFrameArgs args =
+      BeginFrameArgs(frame_time, deadline, interval, type, on_critical_path);
   args.created_from = location;
   return args;
 #endif
@@ -73,6 +78,7 @@ void BeginFrameArgs::AsValueInto(base::trace_event::TracedValue* state) const {
 #ifndef NDEBUG
   state->SetString("created_from", created_from.ToString());
 #endif
+  state->SetBoolean("on_critical_path", on_critical_path);
 }
 
 // This is a hard-coded deadline adjustment that assumes 60Hz, to be used in