Use microsecond timestamp in cricket::VideoFrame.

webrtc/media/base/videoframe.h

Index: webrtc/media/base/videoframe.h
diff --git a/webrtc/media/base/videoframe.h b/webrtc/media/base/videoframe.h
index 6045bc08b4704982788c93656db9c688a3ae9405..792b66e1b96a5409ffe9c36796c596803e24d140 100644
--- a/webrtc/media/base/videoframe.h
+++ b/webrtc/media/base/videoframe.h
@@ -57,8 +57,19 @@ class VideoFrame {
   virtual rtc::scoped_refptr<webrtc::VideoFrameBuffer> GetVideoFrameBuffer()
       const = 0;
 
-  virtual int64_t GetTimeStamp() const = 0;
-  virtual void SetTimeStamp(int64_t time_stamp) = 0;
+  // System monotonic clock, same timebase as rtc::TimeMicros().
+  virtual int64_t timestamp_us() const = 0;
+  virtual void set_timestamp_us(int64_t time_us) = 0;
+
+  // Deprecated methods, for backwards compatibility.
+  // TODO(nisse): Delete when usage in Chrome and other applications
+  // have been replaced.
+  virtual int64_t GetTimeStamp() const {
+    return rtc::kNumNanosecsPerMicrosec * timestamp_us();
+  }
+  virtual void SetTimeStamp(int64_t time_ns) {
+    set_timestamp_us(time_ns / rtc::kNumNanosecsPerMicrosec);
+  }
 
   // Indicates the rotation angle in degrees.
   virtual webrtc::VideoRotation GetVideoRotation() const  = 0;
@@ -138,7 +149,7 @@ class VideoFrame {
 
   // Creates an empty frame.
   virtual VideoFrame *CreateEmptyFrame(int w, int h,
-                                       int64_t time_stamp) const = 0;
+                                       int64_t timestamp_us) const = 0;
   virtual void SetRotation(webrtc::VideoRotation rotation) = 0;
 };