ResizingHostObserver is created by the desktop environment together with other stubs.

remoting/host/chromoting_host.h

 // Copyright (c) 2012 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 REMOTING_HOST_CHROMOTING_HOST_H_
 #define REMOTING_HOST_CHROMOTING_HOST_H_
 
 #include <string>
 #include <vector>
 
@@ skipping 108 matching lines @@
   virtual void OnSessionAuthenticated(ClientSession* client) OVERRIDE;
   virtual void OnSessionChannelsConnected(ClientSession* client) OVERRIDE;
   virtual void OnSessionAuthenticationFailed(ClientSession* client) OVERRIDE;
   virtual void OnSessionClosed(ClientSession* session) OVERRIDE;
   virtual void OnSessionSequenceNumber(ClientSession* session,
                                        int64 sequence_number) OVERRIDE;
   virtual void OnSessionRouteChange(
       ClientSession* session,
       const std::string& channel_name,
       const protocol::TransportRoute& route) OVERRIDE;
-  virtual void OnClientResolutionChanged(ClientSession* session,
-                                         const SkISize& size,
-                                         const SkIPoint& dpi) OVERRIDE;
 
   // SessionManager::Listener implementation.
   virtual void OnSessionManagerReady() OVERRIDE;
   virtual void OnIncomingSession(
       protocol::Session* session,
       protocol::SessionManager::IncomingSessionResponse* response) OVERRIDE;
 
   // MouseMoveObserver interface.
   virtual void OnLocalMouseMoved(const SkIPoint& new_pos) OVERRIDE;
 
@@ skipping 75 matching lines @@
   base::TimeDelta max_session_duration_;
 
   base::WeakPtrFactory<ChromotingHost> weak_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(ChromotingHost);
 };
 
 }  // namespace remoting
 
 #endif  // REMOTING_HOST_CHROMOTING_HOST_H_