Move gtk-specific browser main parts stuff to its own file.

chrome/browser/ui/views/chrome_browser_main_extra_parts_views.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_CHROME_BROWSER_MAIN_EXTRA_PARTS_VIEWS_H_
 #define CHROME_BROWSER_UI_VIEWS_CHROME_BROWSER_MAIN_EXTRA_PARTS_VIEWS_H_
 
 #include "base/macros.h"
 #include "base/memory/scoped_ptr.h"
 #include "chrome/browser/chrome_browser_main_extra_parts.h"
 
 namespace views {
 class ViewsDelegate;
 }
 
 #if defined(USE_AURA)
 namespace wm {
 class WMState;
 }
 #endif
 
 class ChromeBrowserMainExtraPartsViews : public ChromeBrowserMainExtraParts {
  public:
   ChromeBrowserMainExtraPartsViews();
   ~ChromeBrowserMainExtraPartsViews() override;
 
   // Overridden from ChromeBrowserMainExtraParts:
   void ToolkitInitialized() override;
+  void PreCreateThreads() override;
 
  private:
   scoped_ptr<views::ViewsDelegate> views_delegate_;
 
 #if defined(USE_AURA)
   scoped_ptr<wm::WMState> wm_state_;
 #endif
 
   DISALLOW_COPY_AND_ASSIGN(ChromeBrowserMainExtraPartsViews);
 };
 
 #endif  // CHROME_BROWSER_UI_VIEWS_CHROME_BROWSER_MAIN_EXTRA_PARTS_VIEWS_H_