Mojo: Replace RemotePtr with InterfacePtr and InterfaceImpl

mojo/public/cpp/bindings/error_handler.h

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef MOJO_PUBLIC_CPP_BINDINGS_ERROR_HANDLER_H_
 #define MOJO_PUBLIC_CPP_BINDINGS_ERROR_HANDLER_H_
 
 namespace mojo {
 
+// This interface is used to report connection errors.
 class ErrorHandler {
  public:
   virtual ~ErrorHandler() {}
-  virtual void OnError() = 0;
+  virtual void OnConnectionError() = 0;
+};
+
+// Used when you'd like to extend a base class with the same method signature
+// as ErrorHandler.
+template <typename Base>
+class WithErrorHandler : public Base {
+ public:
+  virtual ~WithErrorHandler() {}
+  virtual void OnConnectionError() = 0;
 };
 
 }  // namespace mojo
 
 #endif  // MOJO_PUBLIC_CPP_BINDINGS_ERROR_HANDLER_H_