cc: Save correct frame begin time to FrameRateCounter

cc/frame_rate_controller.cc

 // Copyright 2011 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "cc/frame_rate_controller.h"
 
 #include "base/debug/trace_event.h"
 #include "base/logging.h"
 #include "cc/delay_based_time_source.h"
 #include "cc/time_source.h"
@@ skipping 135 matching lines @@
 }
 
 base::TimeTicks FrameRateController::nextTickTime()
 {
     if (m_isTimeSourceThrottling)
         return m_timeSource->nextTickTime();
 
     return base::TimeTicks();
 }
 
+base::TimeTicks FrameRateController::lastTickTime()
+{
+    if (m_isTimeSourceThrottling)
+        return m_timeSource->lastTickTime();
+
+    return base::TimeTicks::Now();
+}
+
 }  // namespace cc