Add zoom extension API

chrome/common/render_messages_internal.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.
 
 #include <map>
 #include <set>
 #include <string>
 #include <vector>
 
 #include "build/build_config.h"
@@ skipping 406 matching lines @@
 
 // Change the zoom level for the current main frame.  If the level actually
 // changes, a ViewHostMsg_DidZoomURL message will be sent back to the browser
 // telling it what url got zoomed and what its current zoom level is.
 IPC_MESSAGE_ROUTED1(ViewMsg_Zoom,
                     PageZoom::Function /* function */)
 
 // Set the zoom level for the current main frame.  If the level actually
 // changes, a ViewHostMsg_DidZoomURL message will be sent back to the browser
 // telling it what url got zoomed and what its current zoom level is.
-IPC_MESSAGE_ROUTED1(ViewMsg_SetZoomLevel,
+IPC_MESSAGE_ROUTED2(ViewMsg_SetZoomLevel,
+                    int /* request_id */,
                     double /* zoom_level */)
 
 // Set the zoom level for a particular url that the renderer is in the
 // process of loading.  This will be stored, to be used if the load commits
 // and ignored otherwise.
 IPC_MESSAGE_ROUTED2(ViewMsg_SetZoomLevelForLoadingURL,
                     GURL /* url */,
                     double /* zoom_level */)
 
 // Set the zoom level for a particular url, so all render views
@@ skipping 1434 matching lines @@
 
 // Sent by the renderer process to acknowledge receipt of a
 // UploadProgress message.
 IPC_MESSAGE_ROUTED1(ViewHostMsg_UploadProgress_ACK,
                     int /* request_id */)
 
 // Sent when the renderer changes the zoom level for a particular url, so the
 // browser can update its records.  If remember is true, then url is used to
 // update the zoom level for all pages in that site.  Otherwise, the render
 // view's id is used so that only the menu is updated.
-IPC_MESSAGE_ROUTED3(ViewHostMsg_DidZoomURL,
+IPC_MESSAGE_ROUTED4(ViewHostMsg_DidZoomURL,
+                    int /* request_id */,
                     double /* zoom_level */,
                     bool /* remember */,
                     GURL /* url */)
 
 #if defined(OS_WIN)
 // Duplicates a shared memory handle from the renderer to the browser. Then
 // the renderer can flush the handle.
 IPC_SYNC_MESSAGE_ROUTED1_1(ViewHostMsg_DuplicateSection,
                            base::SharedMemoryHandle /* renderer handle */,
                            base::SharedMemoryHandle /* browser handle */)
@@ skipping 628 matching lines @@
 // The currently displayed PDF has an unsupported feature.
 IPC_MESSAGE_ROUTED0(ViewHostMsg_PDFHasUnsupportedFeature)
 
 // JavaScript related messages -----------------------------------------------
 
 // Notify the JavaScript engine in the render to change its parameters
 // while performing stress testing.
 IPC_MESSAGE_ROUTED2(ViewMsg_JavaScriptStressTestControl,
                     int /* cmd */,
                     int /* param */)