chrome: Cleanup class/struct forward declarations

chrome/browser/first_run/try_chrome_dialog_view.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_FIRST_RUN_TRY_CHROME_DIALOG_VIEW_H_
 #define CHROME_BROWSER_FIRST_RUN_TRY_CHROME_DIALOG_VIEW_H_
 
 #include <stddef.h>
 
 #include "base/compiler_specific.h"
 #include "base/macros.h"
 #include "ui/gfx/native_widget_types.h"
 #include "ui/views/controls/button/button.h"
 #include "ui/views/controls/link_listener.h"
 
-class ProcessSingleton;
-
 namespace gfx {
 class Rect;
 }
 
 namespace views {
 class RadioButton;
 class Checkbox;
 class Widget;
 }
 
@@ skipping 93 matching lines @@
   views::RadioButton* try_chrome_;
   views::RadioButton* kill_chrome_;
   views::RadioButton* dont_try_chrome_;
   views::Checkbox* make_default_;
   Result result_;
 
   DISALLOW_COPY_AND_ASSIGN(TryChromeDialogView);
 };
 
 #endif  // CHROME_BROWSER_FIRST_RUN_TRY_CHROME_DIALOG_VIEW_H_