Delete obviously unneeded forward declarations in chrome/browser/*.h.

chrome/browser/tab_menu_model.h

 // Copyright (c) 2010 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_TAB_MENU_MODEL_H_
 #define CHROME_BROWSER_TAB_MENU_MODEL_H_
 #pragma once
 
 #include "app/menus/simple_menu_model.h"
 
-class Browser;
-
 // A menu model that builds the contents of the tab context menu. This menu has
 // only one level (no submenus). TabMenuModel caches local state from the
 // tab (such as the pinned state). To make sure the menu reflects the real state
 // of the tab a new TabMenuModel should be created each time the menu is shown.
 class TabMenuModel : public menus::SimpleMenuModel {
  public:
   TabMenuModel(menus::SimpleMenuModel::Delegate* delegate, bool is_pinned);
   virtual ~TabMenuModel() {}
 
   // Returns true if vertical tabs are enabled.
   static bool AreVerticalTabsEnabled();
 
  private:
   void Build(bool is_pinned);
 
   DISALLOW_COPY_AND_ASSIGN(TabMenuModel);
 };
 
 #endif  // CHROME_BROWSER_TAB_MENU_MODEL_H_