Change SetOutputScaling to set a single level, not left/right levels.

talk/media/base/mediachannel.h

Index: talk/media/base/mediachannel.h
diff --git a/talk/media/base/mediachannel.h b/talk/media/base/mediachannel.h
index bf06e236861ed01e8d6ba63b3735e2cb629e3ca5..90ed89388d9fe5758dc298b83013222769308c03 100644
--- a/talk/media/base/mediachannel.h
+++ b/talk/media/base/mediachannel.h
@@ -1086,8 +1086,8 @@ class VoiceMediaChannel : public MediaChannel {
   virtual void SetTypingDetectionParameters(int time_window,
     int cost_per_typing, int reporting_threshold, int penalty_decay,
     int type_event_delay) = 0;
-  // Set left and right scale for speaker output volume of the specified ssrc.
-  virtual bool SetOutputScaling(uint32_t ssrc, double left, double right) = 0;
+  // Set speaker output volume of the specified ssrc.
+  virtual bool SetOutputVolume(uint32_t ssrc, double volume) = 0;
   // Returns if the telephone-event has been negotiated.
   virtual bool CanInsertDtmf() { return false; }
   // Send and/or play a DTMF |event| according to the |flags|.