Improve wraparound handling in the render time extrapolator.

This was actually working as intended, but as r3970 changed when render timestamps were extrapolated to when a frame was taken out for decoding, the wraparound could have happened in the Update() step before it had happened in the ExtrapolateLocalTime() step. This causes render timestamps to be generated 13 hours into the future.

TEST=trybots
BUG=1787
R=mflodman@webrtc.org

Review URL: https://webrtc-codereview.appspot.com/1497004

git-svn-id: http://webrtc.googlecode.com/svn/trunk@4055 4adac7df-926f-26a2-2b94-8c16560cd09d

webrtc/modules/video_coding/main/source/timing.h

@@ -33,7 +33,7 @@ public:
     ~VCMTiming();
 
     // Resets the timing to the initial state.
-    void Reset(int64_t nowMs = -1);
+    void Reset();
     void ResetDecodeTime();
 
     // The amount of time needed to render an image. Defaults to 10 ms.