Make the metro viewer responsible for relaunching browser in desktop mode.

ui/metro_viewer/metro_viewer_messages.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.
 
 // Multiply-included message file, no include guard.
 
 #include <vector>
 
 #include "base/basictypes.h"
 #include "ipc/ipc_message_macros.h"
@@ skipping 74 matching lines @@
                      bool,                    /* success */
                      std::vector<base::FilePath>)   /* filenames */
 
 // Informs the browser of the result of a select folder operation.
 IPC_MESSAGE_CONTROL2(MetroViewerHostMsg_SelectFolderDone,
                      bool,           /* success */
                      base::FilePath) /* filepath*/
 
 // Messages sent from the browser to the viewer:
 
+// Requests the viewer to open a URL in desktop mode.
+IPC_MESSAGE_CONTROL2(MetroViewerHostMsg_OpenURLOnDesktop,
+                     base::FilePath,  /* shortcut */
+                     string16         /* url */);
+
 // Requests the viewer to change the pointer to a new cursor.
 IPC_MESSAGE_CONTROL1(MetroViewerHostMsg_SetCursor,
                      int64         /* cursor */);
 
 // This structure contains the parameters sent to the viewer process to display
 // the file save dialog.
 IPC_STRUCT_BEGIN(MetroViewerHostMsg_SaveAsDialogParams)
 
   // The title of the file save dialog if any.
   IPC_STRUCT_MEMBER(string16, title)
@@ skipping 45 matching lines @@
                      string16)  /* url */
 
 IPC_MESSAGE_CONTROL1(MetroViewerHostMsg_SearchRequest,
                      string16)  /* search_string */
 
 // Sent from the metro viewer process to the browser process to indicate that
 // the viewer window size has changed.
 IPC_MESSAGE_CONTROL2(MetroViewerHostMsg_WindowSizeChanged,
                      uint32,   /* width */
                      uint32)   /* height */