Use ThreadNow() for recording times.

cc/debug/rendering_stats_instrumentation.cc

Index: cc/debug/rendering_stats_instrumentation.cc
diff --git a/cc/debug/rendering_stats_instrumentation.cc b/cc/debug/rendering_stats_instrumentation.cc
index 2c5b2523b1009f933d32a181979bd0d7e9651f5a..3c2c96b8b00b42f1722750ee77110a64d5423de5 100644
--- a/cc/debug/rendering_stats_instrumentation.cc
+++ b/cc/debug/rendering_stats_instrumentation.cc
@@ -39,15 +39,21 @@ void RenderingStatsInstrumentation::AccumulateAndClearImplThreadStats() {
 }
 
 base::TimeTicks RenderingStatsInstrumentation::StartRecording() const {
-  if (record_rendering_stats_)
+  if (record_rendering_stats_) {
+    if (base::TimeTicks::IsThreadNowSupported())
+      return base::TimeTicks::ThreadNow();
     return base::TimeTicks::HighResNow();
+  }
   return base::TimeTicks();
 }
 
 base::TimeDelta RenderingStatsInstrumentation::EndRecording(
     base::TimeTicks start_time) const {
-  if (!start_time.is_null())
+  if (!start_time.is_null()) {
+    if (base::TimeTicks::IsThreadNowSupported())
+      return base::TimeTicks::ThreadNow() - start_time;
     return base::TimeTicks::HighResNow() - start_time;
+  }
   return base::TimeDelta();
 }