Remove PrepareForShutdown

ui/aura/remote_window_tree_host_win.cc

 // 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.
 
 #include "ui/aura/remote_window_tree_host_win.h"
 
 #include <windows.h>
 
 #include <algorithm>
 
@@ skipping 467 matching lines @@
 
 void RemoteWindowTreeHostWin::PostNativeEvent(
     const base::NativeEvent& native_event) {
 }
 
 void RemoteWindowTreeHostWin::OnDeviceScaleFactorChanged(
     float device_scale_factor) {
   NOTIMPLEMENTED();
 }
 
-void RemoteWindowTreeHostWin::PrepareForShutdown() {
-}
-
 ui::EventProcessor* RemoteWindowTreeHostWin::GetEventProcessor() {
   return dispatcher();
 }
 
 void RemoteWindowTreeHostWin::CancelComposition() {
   if (!host_)
     return;
   host_->Send(new MetroViewerHostMsg_ImeCancelComposition);
 }
 
@@ skipping 267 matching lines @@
 }
 
 void RemoteWindowTreeHostWin::SetEventFlags(uint32 flags) {
   if (flags == event_flags_)
     return;
   event_flags_ = flags;
   SetVirtualKeyStates(event_flags_);
 }
 
 }  // namespace aura