Fixes crash in RemoteWindowTreeHostWin::HandleActivateDesktop

chrome/browser/metro_viewer/chrome_metro_viewer_process_host_aurawin.h

 // Copyright 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 CHROME_BROWSER_METRO_VIEWER_CHROME_METRO_VIEWER_PROCESS_HOST_AURAWIN_H_
 #define CHROME_BROWSER_METRO_VIEWER_CHROME_METRO_VIEWER_PROCESS_HOST_AURAWIN_H_
 
 #include "win8/viewer/metro_viewer_process_host.h"
 
+namespace base {
+class FilePath;
+}
+
+// Handles the activate desktop command for Metro Chrome Ash.   The |ash_exit|
+// parameter indicates whether the Ash process would be shutdown after
+// activating the desktop.
+void HandleActivateDesktop(const base::FilePath& shortcut, bool ash_exit);
+
 class ChromeMetroViewerProcessHost : public win8::MetroViewerProcessHost {
  public:
   ChromeMetroViewerProcessHost();
+  virtual ~ChromeMetroViewerProcessHost();
+
+  // Returns the singleton ChromeMetroViewerProcessHost instance. This may
+  // return NULL.
+  static ChromeMetroViewerProcessHost* instance() {
+    return instance_;
+  }
 
  private:
   // win8::MetroViewerProcessHost implementation
   virtual void OnChannelError() OVERRIDE;
   // IPC::Listener implementation
   virtual void OnChannelConnected(int32 peer_pid) OVERRIDE;
   virtual void OnSetTargetSurface(gfx::NativeViewId target_surface,
                                   float device_scale) OVERRIDE;
   virtual void OnOpenURL(const base::string16& url) OVERRIDE;
   virtual void OnHandleSearchRequest(
       const base::string16& search_string) OVERRIDE;
   virtual void OnWindowSizeChanged(uint32 width, uint32 height) OVERRIDE;
 
+  static ChromeMetroViewerProcessHost* instance_;
+
   DISALLOW_COPY_AND_ASSIGN(ChromeMetroViewerProcessHost);
 };
 
 #endif  // CHROME_BROWSER_METRO_VIEWER_CHROME_METRO_VIEWER_PROCESS_HOST_AURAWIN_H_