Rejigger ThemeService: move exposure of ThemeProvider interface to a

chrome/browser/ui/views/frame/browser_frame.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_UI_VIEWS_FRAME_BROWSER_FRAME_H_
 #define CHROME_BROWSER_UI_VIEWS_FRAME_BROWSER_FRAME_H_
 
 #include "base/compiler_specific.h"
 #include "base/logging.h"
 #include "build/build_config.h"
@@ skipping 127 matching lines @@
 
   // Used to show the system menu. Only used if
   // NativeBrowserFrame::UsesNativeSystemMenu() returns false.
   scoped_ptr<views::MenuRunner> menu_runner_;
 
   // SetThemeProvider() triggers setting both |owned_theme_provider_| and
   // |theme_provider_|. Initially |theme_provider_| is set to the ThemeService
   // and |owned_theme_provider_| is null (as ThemeServices lifetime is managed
   // externally).
   scoped_ptr<ui::ThemeProvider> owned_theme_provider_;
-  ui::ThemeProvider* theme_provider_;
+  const ui::ThemeProvider* theme_provider_;
 
   scoped_ptr<ui::EventHandler> browser_command_handler_;
 
   DISALLOW_COPY_AND_ASSIGN(BrowserFrame);
 };
 
 #endif  // CHROME_BROWSER_UI_VIEWS_FRAME_BROWSER_FRAME_H_