VCM: Adding API for the size(duration) of the jitter buffer.

Refers to the duration in time of the frames which are ready to be sent to the decoder.

Review URL: https://webrtc-codereview.appspot.com/1319004

git-svn-id: http://webrtc.googlecode.com/svn/trunk@3903 4adac7df-926f-26a2-2b94-8c16560cd09d

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

@@ -412,6 +412,10 @@ public:
     //                     < 0,         on error.
     virtual int32_t Decode(uint16_t maxWaitTimeMs = 200) = 0;
 
+    // Registers a callback which conveys the size of the render buffer.
+    virtual int RegisterRenderBufferSizeCallback(
+        VCMRenderBufferSizeCallback* callback) = 0;
+
     // Waits for the next frame in the dual jitter buffer to become complete
     // (waits no longer than maxWaitTimeMs), then passes it to the dual decoder
     // for decoding. This will never trigger a render callback. Should be

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

@@ -182,6 +182,17 @@ class VCMQMSettingsCallback {
   }
 };
 
+// Callback class used for telling the user about the size (in time) of the
+// render buffer, that is the size in time of the complete continuous frames.
+class VCMRenderBufferSizeCallback {
+ public:
+  virtual void RenderBufferSizeMs(int buffer_size_ms) = 0;
+
+ protected:
+  virtual ~VCMRenderBufferSizeCallback() {
+  }
+};
+
 }  // namespace webrtc
 
 #endif // WEBRTC_MODULES_INTERFACE_VIDEO_CODING_DEFINES_H_