Add suport for changing cursors

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 "base/basictypes.h"
 #include "ipc/ipc_message_macros.h"
 #include "ui/base/events/event_constants.h"
 #include "ui/gfx/native_widget_types.h"
 
 #define IPC_MESSAGE_START MetroViewerMsgStart
 
 IPC_ENUM_TRAITS(ui::EventType)
 IPC_ENUM_TRAITS(ui::EventFlags)
 
-// Messages sent from the viewer to the browser.
+// Messages sent from the viewer to the browser:
 
 // Inform the browser of the surface to target for compositing.
 IPC_MESSAGE_CONTROL1(MetroViewerHostMsg_SetTargetSurface,
                      gfx::NativeViewId /* target hwnd */)
 // Informs the browser that the mouse moved.
 IPC_MESSAGE_CONTROL3(MetroViewerHostMsg_MouseMoved,
                      int32,       /* x-coordinate */
                      int32,       /* y-coordinate */
                      int32        /* flags */)
 // Informs the brower that a mouse button was pressed.
@@ skipping 16 matching lines @@
                      uint32,       /* scan code */
                      uint32        /* key state */);
 IPC_MESSAGE_CONTROL4(MetroViewerHostMsg_Character,
                      uint32,       /* virtual key */
                      uint32,       /* repeat count */
                      uint32,       /* scan code */
                      uint32        /* key state */);
 // Informs the browser that the visibiliy of the viewer has changed.
 IPC_MESSAGE_CONTROL1(MetroViewerHostMsg_VisibilityChanged,
                      bool          /* visible */);
+
+// Messages sent from the browser to the viewer:
+
+// Requests the viewer to change the pointer to a new cursor.
+IPC_MESSAGE_CONTROL1(MetroViewerHostMsg_SetCursor,
+                     int64         /* cursor */);