Move extension messages to their own file and add a RenderViewObserver to start moving the extens...

content/common/view_messages.h

 // Copyright (c) 2011 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 "content/common/common_param_traits.h"
@@ skipping 1217 matching lines @@
                     ViewHostMsg_ShowPopup_Params)
 
 // Response from ViewMsg_ScriptEvalRequest. The ID is the parameter supplied
 // to ViewMsg_ScriptEvalRequest. The result has the value returned by the
 // script as it's only element, one of Null, Boolean, Integer, Real, Date, or
 // String.
 IPC_MESSAGE_ROUTED2(ViewHostMsg_ScriptEvalResponse,
                     int  /* id */,
                     ListValue  /* result */)
 
+// Sent by the renderer process to acknowledge receipt of a
+// ViewMsg_CSSInsertRequest message and css has been inserted into the frame.
+IPC_MESSAGE_ROUTED0(ViewHostMsg_OnCSSInserted)
+
 // Result of string search in the page.
 // Response to ViewMsg_Find with the results of the requested find-in-page
 // search, the number of matches found and the selection rect (in screen
 // coordinates) for the string found. If |final_update| is false, it signals
 // that this is not the last Find_Reply message - more will be sent as the
 // scoping effort continues.
 IPC_MESSAGE_ROUTED5(ViewHostMsg_Find_Reply,
                     int /* request_id */,
                     int /* number of matches */,
                     gfx::Rect /* selection_rect */,
@@ skipping 603 matching lines @@
 // enable or disable spdy.  Used for debugging/testing/benchmarking.
 IPC_MESSAGE_CONTROL1(ViewHostMsg_EnableSpdy,
                      bool /* enable */)
 
 // Message sent from the renderer to the browser to request that the browser
 // cache |data| associated with |url|.
 IPC_MESSAGE_CONTROL3(ViewHostMsg_DidGenerateCacheableMetadata,
                      GURL /* url */,
                      double /* expected_response_time */,
                      std::vector<char> /* data */)