[DevTools] Handle frontend zoom similarly to tab zoom.

chrome/browser/devtools/devtools_window.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.
 
 #ifndef CHROME_BROWSER_DEVTOOLS_DEVTOOLS_WINDOW_H_
 #define CHROME_BROWSER_DEVTOOLS_DEVTOOLS_WINDOW_H_
 
 #include <string>
 #include <vector>
 
@@ skipping 248 matching lines @@
   virtual content::WebContents* OpenURLFromTab(
       content::WebContents* source,
       const content::OpenURLParams& params) OVERRIDE;
   virtual void AddNewContents(content::WebContents* source,
                               content::WebContents* new_contents,
                               WindowOpenDisposition disposition,
                               const gfx::Rect& initial_pos,
                               bool user_gesture,
                               bool* was_blocked) OVERRIDE;
   virtual void CloseContents(content::WebContents* source) OVERRIDE;
+  virtual void ContentsZoomChange(bool zoom_in) OVERRIDE;
   virtual void BeforeUnloadFired(content::WebContents* tab,
                                  bool proceed,
                                  bool* proceed_to_fire_unload) OVERRIDE;
   virtual bool PreHandleKeyboardEvent(
       content::WebContents* source,
       const content::NativeWebKeyboardEvent& event,
       bool* is_keyboard_shortcut) OVERRIDE;
   virtual void HandleKeyboardEvent(
       content::WebContents* source,
       const content::NativeWebKeyboardEvent& event) OVERRIDE;
@@ skipping 108 matching lines @@
   // from the inspected webcontents, see InterceptPageBeforeUnload for details.
   bool intercepted_page_beforeunload_;
 
   scoped_ptr<DevToolsEmbedderMessageDispatcher> embedder_message_dispatcher_;
   base::WeakPtrFactory<DevToolsWindow> weak_factory_;
   base::TimeTicks inspect_element_start_time_;
   DISALLOW_COPY_AND_ASSIGN(DevToolsWindow);
 };
 
 #endif  // CHROME_BROWSER_DEVTOOLS_DEVTOOLS_WINDOW_H_