Add zoom extension API

chrome/browser/renderer_host/render_view_host.cc

 // 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 "chrome/browser/renderer_host/render_view_host.h"
 
 #include <string>
 #include <utility>
 #include <vector>
 
@@ skipping 396 matching lines @@
       NOTREACHED();
       params.action = ViewMsg_StopFinding_Params::kKeepSelection;
   }
   Send(new ViewMsg_StopFinding(routing_id(), params));
 }
 
 void RenderViewHost::Zoom(PageZoom::Function function) {
   Send(new ViewMsg_Zoom(routing_id(), function));
 }
 
-void RenderViewHost::SetZoomLevel(double zoom_level) {
-  Send(new ViewMsg_SetZoomLevel(routing_id(), zoom_level));
+void RenderViewHost::SetZoomLevel(int request_id, double zoom_level) {
+  Send(new ViewMsg_SetZoomLevel(routing_id(), request_id, zoom_level));
 }
 
 void RenderViewHost::SetPageEncoding(const std::string& encoding_name) {
   Send(new ViewMsg_SetPageEncoding(routing_id(), encoding_name));
 }
 
 void RenderViewHost::ResetPageEncodingToDefault() {
   Send(new ViewMsg_ResetPageEncodingToDefault(routing_id()));
 }
 
@@ skipping 1286 matching lines @@
     LOG(DFATAL) << "Invalid checked state " << checked_state;
     return;
   }
 
   CommandState state;
   state.is_enabled = is_enabled;
   state.checked_state =
       static_cast<RenderViewCommandCheckedState>(checked_state);
   command_states_[static_cast<RenderViewCommand>(command)] = state;
 }