Add zoom extension API

chrome/browser/renderer_host/render_view_host.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.
 
 #ifndef CHROME_BROWSER_RENDERER_HOST_RENDER_VIEW_HOST_H_
 #define CHROME_BROWSER_RENDERER_HOST_RENDER_VIEW_HOST_H_
 #pragma once
 
 #include <string>
 #include <vector>
@@ skipping 215 matching lines @@
                     bool match_case,
                     bool find_next);
 
   // Cancel a pending find operation.
   void StopFinding(FindBarController::SelectionAction selection_action);
 
   // Increment, decrement, or reset the zoom level of a page.
   void Zoom(PageZoom::Function function);
 
   // Change the zoom level of a page to a specific value.
-  void SetZoomLevel(double zoom_level);
+  void SetZoomLevel(int request_id, double zoom_level);
 
   // Change the encoding of the page.
   void SetPageEncoding(const std::string& encoding);
 
   // Reset any override encoding on the page and change back to default.
   void ResetPageEncodingToDefault();
 
   // Change the alternate error page URL.  An empty GURL disables the use of
   // alternate error pages.
   void SetAlternateErrorPageURL(const GURL& url);
@@ skipping 483 matching lines @@
   // The termination status of the last render view that terminated.
   base::TerminationStatus render_view_termination_status_;
 
   // The enabled/disabled states of various commands.
   std::map<RenderViewCommand, CommandState> command_states_;
 
   DISALLOW_COPY_AND_ASSIGN(RenderViewHost);
 };
 
 #endif  // CHROME_BROWSER_RENDERER_HOST_RENDER_VIEW_HOST_H_