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

chrome/browser/ui/aura/chrome_browser_main_extra_parts_aura.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_AURA_CHROME_BROWSER_MAIN_EXTRA_PARTS_AURA_H_
-#define CHROME_BROWSER_UI_AURA_CHROME_BROWSER_MAIN_EXTRA_PARTS_AURA_H_
-
-#include "base/compiler_specific.h"
-#include "base/macros.h"
-#include "base/memory/scoped_ptr.h"
-#include "build/build_config.h"
-#include "chrome/browser/chrome_browser_main_extra_parts.h"
-
-class ChromeBrowserMainExtraPartsAura : public ChromeBrowserMainExtraParts {
- public:
-  ChromeBrowserMainExtraPartsAura();
-  ~ChromeBrowserMainExtraPartsAura() override;
-
-  // Overridden from ChromeBrowserMainExtraParts:
-  void PreEarlyInitialization() override;
-  void ToolkitInitialized() override;
-  void PreCreateThreads() override;
-  void PreProfileInit() override;
-  void PostMainMessageLoopRun() override;
-
- private:
-#if defined(OS_LINUX) && !defined(OS_CHROMEOS)
-  // On the Linux desktop, we want to prevent the user from logging in as root,
-  // so that we don't destroy the profile.
-  void DetectRunningAsRoot();
-#endif
-
-  DISALLOW_COPY_AND_ASSIGN(ChromeBrowserMainExtraPartsAura);
-};
-
-#endif  // CHROME_BROWSER_UI_AURA_CHROME_BROWSER_MAIN_EXTRA_PARTS_AURA_H_