Differentiate invisible cursor mode and disabled mouse events mode.

content/common/view_messages.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.
 
 // IPC messages for page rendering.
 // Multiply-included message file, hence no include guard.
 
 #include "base/process.h"
 #include "base/shared_memory.h"
 #include "base/string16.h"
@@ skipping 1807 matching lines @@
                            bool         /* out - success */,
                            string16     /* out - user_input field */)
 
 // Requests that the given URL be opened in the specified manner.
 IPC_MESSAGE_ROUTED1(ViewHostMsg_OpenURL, ViewHostMsg_OpenURL_Params)
 
 // Notifies that the preferred size of the content changed.
 IPC_MESSAGE_ROUTED1(ViewHostMsg_DidContentsPreferredSizeChange,
                     gfx::Size /* pref_size */)
 
+// Notifies that the scroll offset changed.
+// This is different from ViewHostMsg_UpdateRect in that ViewHostMsg_UpdateRect
+// is not sent at all when threaded compositing is enabled while
+// ViewHostMsg_DidChangeScrollOffset works properly in this case.
+IPC_MESSAGE_ROUTED0(ViewHostMsg_DidChangeScrollOffset)
+
 // Notifies that the scrollbars-visible state of the content changed.
 IPC_MESSAGE_ROUTED2(ViewHostMsg_DidChangeScrollOffsetPinningForMainFrame,
                     bool /* has_horizontal_scrollbar */,
                     bool /* has_vertical_scrollbar */)
 
 // Notifies that the pinned-to-side state of the content changed.
 IPC_MESSAGE_ROUTED2(ViewHostMsg_DidChangeScrollbarsForMainFrame,
                     bool /* pinned_to_left */,
                     bool /* pinned_to_right */)
 
@@ skipping 536 matching lines @@
 // cached by the OS. Please see RenderMessageFilter::OnPreCacheFontCharacters
 // for details.
 IPC_SYNC_MESSAGE_CONTROL2_0(ViewHostMsg_PreCacheFontCharacters,
                             LOGFONT /* font_data */,
                             string16 /* characters */)
 #endif
 
 // Notifies the browser that the frame with the given id was detached.
 IPC_MESSAGE_ROUTED1(ViewHostMsg_FrameDetached,
                     int64 /* frame_id */)