Add OVERRIDE to remoting/.

remoting/client/plugin/pepper_xmpp_proxy.h

Index: remoting/client/plugin/pepper_xmpp_proxy.h
diff --git a/remoting/client/plugin/pepper_xmpp_proxy.h b/remoting/client/plugin/pepper_xmpp_proxy.h
index 189572ccca0853691421d75df0f5ae47d3204e9f..cc3e690e9f4e16a75b2770e123f4d86fdb7deaa3 100644
--- a/remoting/client/plugin/pepper_xmpp_proxy.h
+++ b/remoting/client/plugin/pepper_xmpp_proxy.h
@@ -33,10 +33,11 @@ class PepperXmppProxy : public XmppProxy {
   // create a WeakPtr on, say the pepper thread, and then pass execution of
   // this function callback with the weak pointer bound as a parameter.  That
   // will fail because the WeakPtr will have been created on the wrong thread.
-  virtual void AttachCallback(base::WeakPtr<ResponseCallback> callback);
-  virtual void DetachCallback();
+  virtual void AttachCallback(
+      base::WeakPtr<ResponseCallback> callback) OVERRIDE;
+  virtual void DetachCallback() OVERRIDE;
 
-  virtual void SendIq(const std::string& request_xml);
+  virtual void SendIq(const std::string& request_xml) OVERRIDE;
   virtual void OnIq(const std::string& response_xml);
 
  private: