Cleanup: Remove duplicated functions

talk/app/webrtc/peerconnectioninterface.h

Index: talk/app/webrtc/peerconnectioninterface.h
diff --git a/talk/app/webrtc/peerconnectioninterface.h b/talk/app/webrtc/peerconnectioninterface.h
index a3af0e715c7fc0422eed011f8bafc7c6d5ad7c4f..ca853385e6327fdcad52014b32abc115685e80c1 100644
--- a/talk/app/webrtc/peerconnectioninterface.h
+++ b/talk/app/webrtc/peerconnectioninterface.h
@@ -127,12 +127,6 @@ class StatsObserver : public rtc::RefCountInterface {
 
 class MetricsObserverInterface : public rtc::RefCountInterface {
  public:
-  // TODO(guoweis): Remove this function once IncrementEnumCounter gets into
-  // chromium. IncrementCounter only deals with one type of enumeration counter,
-  // i.e. PeerConnectionAddressFamilyCounter. Instead of creating a function for
-  // each enum type, IncrementEnumCounter is generalized with the enum type
-  // parameter.
-  virtual void IncrementCounter(PeerConnectionAddressFamilyCounter type) {}
 
   // |type| is the type of the enum counter to be incremented. |counter|
   // is the particular counter in that type. |counter_max| is the next sequence