cc: Use HighResNow as timebase if it is fast and reliable

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 47c27ed3f8e41c42753bab991df299a05330aaa9..ab5af653bd43b33ddbbec6e8c8de1ebb59f79594 100644
--- a/cc/scheduler/frame_rate_controller.cc
+++ b/cc/scheduler/frame_rate_controller.cc
@@ -11,6 +11,7 @@
 #include "base/single_thread_task_runner.h"
 #include "cc/scheduler/delay_based_time_source.h"
 #include "cc/scheduler/time_source.h"
+#include "ui/gfx/frame_time.h"
 
 namespace cc {
 
@@ -96,6 +97,9 @@ void FrameRateController::SetMaxSwapsPending(int max_swaps_pending) {
 
 void FrameRateController::SetTimebaseAndInterval(base::TimeTicks timebase,
                                                  base::TimeDelta interval) {
+  if (!gfx::FrameTime::TimestampsAreHighRes())
+    timebase = base::TimeTicks();
+
   interval_ = interval;
   if (is_time_source_throttling_)
     time_source_->SetTimebaseAndInterval(timebase, interval);
@@ -165,7 +169,7 @@ base::TimeTicks FrameRateController::LastTickTime() {
   if (is_time_source_throttling_)
     return time_source_->LastTickTime();
 
-  return base::TimeTicks::Now();
+  return gfx::FrameTime::Now();
 }
 
 }  // namespace cc