Remove browser-side tracking of accelerated compositing

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/memory/shared_memory.h"
 #include "base/process/process.h"
 #include "base/strings/string16.h"
@@ skipping 1163 matching lines @@
 
 // Sent to update part of the view.  In response to this message, the host
 // generates a ViewMsg_UpdateRect_ACK message.
 IPC_MESSAGE_ROUTED1(ViewHostMsg_UpdateRect,
                     ViewHostMsg_UpdateRect_Params)
 
 // Sent to unblock the browser's UI thread if it is waiting on an UpdateRect,
 // which may get delayed until the browser's UI unblocks.
 IPC_MESSAGE_ROUTED0(ViewHostMsg_UpdateIsDelayed)
 
-// Sent by the renderer when accelerated compositing is enabled or disabled to
-// notify the browser whether or not is should do painting.
-IPC_MESSAGE_ROUTED1(ViewHostMsg_DidActivateAcceleratedCompositing,
-                    bool /* true if the accelerated compositor is actve */)
-
 IPC_MESSAGE_ROUTED0(ViewHostMsg_Focus)
 IPC_MESSAGE_ROUTED0(ViewHostMsg_Blur)
 
 // Message sent from renderer to the browser when focus changes inside the
 // webpage. The parameter says whether the newly focused element needs
 // keyboard input (true for textfields, text areas and content editable divs).
 IPC_MESSAGE_ROUTED1(ViewHostMsg_FocusedNodeChanged,
     bool /* is_editable_node */)
 
 IPC_MESSAGE_ROUTED1(ViewHostMsg_SetCursor, content::WebCursor)
@@ skipping 581 matching lines @@
 // synchronously (see crbug.com/120597). This IPC message sends the character
 // bounds after every composition change to always have correct bound info.
 IPC_MESSAGE_ROUTED2(ViewHostMsg_ImeCompositionRangeChanged,
                     gfx::Range /* composition range */,
                     std::vector<gfx::Rect> /* character bounds */)
 #endif
 
 // Adding a new message? Stick to the sort order above: first platform
 // independent ViewMsg, then ifdefs for platform specific ViewMsg, then platform
 // independent ViewHostMsg, then ifdefs for platform specific ViewHostMsg.