1. Override and virtual has to be consistent.
2. provide an implementation for SetIceConnectionReceivingTimeout so that Chrome does not complain.

BUG=

Review URL: https://codereview.webrtc.org/1227843006

Cr-Commit-Position: refs/heads/master@{#9574}
diff --git a/talk/app/webrtc/peerconnectioninterface.h b/talk/app/webrtc/peerconnectioninterface.h
index 367bafe..ce32b50 100644
--- a/talk/app/webrtc/peerconnectioninterface.h
+++ b/talk/app/webrtc/peerconnectioninterface.h
@@ -336,7 +336,7 @@
   virtual void SetRemoteDescription(SetSessionDescriptionObserver* observer,
                                     SessionDescriptionInterface* desc) = 0;
   // Sets the ICE connection receiving timeout value in milliseconds.
-  virtual void SetIceConnectionReceivingTimeout(int timeout_ms) = 0;
+  virtual void SetIceConnectionReceivingTimeout(int timeout_ms) {}
   // Restarts or updates the ICE Agent process of gathering local candidates
   // and pinging remote candidates.
   virtual bool UpdateIce(const IceServers& configuration,