Only allow to lock the mouse when the tab is in fullscreen mode.

content/browser/tab_contents/tab_contents.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 CONTENT_BROWSER_TAB_CONTENTS_TAB_CONTENTS_H_
 #define CONTENT_BROWSER_TAB_CONTENTS_TAB_CONTENTS_H_
 #pragma once
 
 #include <deque>
 #include <map>
@@ skipping 710 matching lines @@
   virtual bool PreHandleKeyboardEvent(const NativeWebKeyboardEvent& event,
                                       bool* is_keyboard_shortcut) OVERRIDE;
   virtual void HandleKeyboardEvent(
       const NativeWebKeyboardEvent& event) OVERRIDE;
   virtual void HandleMouseUp() OVERRIDE;
   virtual void HandleMouseActivate() OVERRIDE;
   virtual bool OnMessageReceived(const IPC::Message& message);
   virtual void RunFileChooser(RenderViewHost* render_view_host,
                               const ViewHostMsg_RunFileChooser_Params& params);
   virtual void ToggleFullscreenMode(bool enter_fullscreen) OVERRIDE;
+  virtual bool IsFullscreenForCurrentTab() const OVERRIDE;
   virtual void UpdatePreferredSize(const gfx::Size& pref_size) OVERRIDE;
 
   // RenderViewHostManager::Delegate -------------------------------------------
 
   // Blocks/unblocks interaction with renderer process.
   void BlockTabContent(bool blocked);
 
   virtual void BeforeUnloadFiredFromRenderManager(
       bool proceed,
       bool* proceed_to_fire_unload);
@@ skipping 146 matching lines @@
   ObserverList<TabContentsObserver> observers_;
 
   // Content restrictions, used to disable print/copy etc based on content's
   // (full-page plugins for now only) permissions.
   int content_restrictions_;
 
   DISALLOW_COPY_AND_ASSIGN(TabContents);
 };
 
 #endif  // CONTENT_BROWSER_TAB_CONTENTS_TAB_CONTENTS_H_