Expose VideoCodingModule's decoder stats up the stack from VCMTiming to chrome://webrtc-internals.

R=juberti@google.com, mikhal@webrtc.org, stefan@webrtc.org, wu@webrtc.org

Review URL: https://webrtc-codereview.appspot.com/2429004

git-svn-id: http://webrtc.googlecode.com/svn/trunk@5027 4adac7df-926f-26a2-2b94-8c16560cd09d

webrtc/modules/video_coding/main/interface/video_coding.h

@@ -376,6 +376,18 @@ public:
     virtual int32_t RegisterReceiveStatisticsCallback(
                                VCMReceiveStatisticsCallback* receiveStats) = 0;
 
+    // Register a decoder timing callback which will be called to deliver
+    // information about the timing of the decoder in the receiving side of the
+    // VCM, for instance the current and maximum frame decode latency.
+    //
+    // Input:
+    //      - decoderTiming  : The callback object to register.
+    //
+    // Return value      : VCM_OK, on success.
+    //                     < 0,         on error.
+    virtual int32_t RegisterDecoderTimingCallback(
+        VCMDecoderTimingCallback* decoderTiming) = 0;
+
     // Register a frame type request callback. This callback will be called when the
     // module needs to request specific frame types from the send side.
     //