Cleanup: Remove unneeded forward declarations in views.

views/widget/widget.h

 // Copyright (c) 2011 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 VIEWS_WIDGET_WIDGET_H_
 #define VIEWS_WIDGET_WIDGET_H_
 #pragma once
 
+#include <set>
 #include <stack>
 
 #include "base/gtest_prod_util.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/observer_list.h"
 #include "ui/base/accessibility/accessibility_types.h"
 #include "ui/base/ui_base_types.h"
 #include "ui/gfx/native_widget_types.h"
 #include "ui/gfx/rect.h"
 #include "ui/views/window/client_view.h"
 #include "ui/views/window/non_client_view.h"
 #include "views/focus/focus_manager.h"
 #include "views/widget/native_widget_delegate.h"
 
 #if defined(OS_WIN)
 // Windows headers define macros for these function names which screw with us.
 #if defined(IsMaximized)
 #undef IsMaximized
 #endif
 #if defined(IsMinimized)
 #undef IsMinimized
 #endif
 #if defined(CreateWindow)
 #undef CreateWindow
 #endif
 #endif
 
 namespace gfx {
 class Canvas;
-class Path;
 class Point;
 class Rect;
 }
 
 namespace ui {
 class Accelerator;
 class Compositor;
 class OSExchangeData;
 class ThemeProvider;
 enum TouchStatus;
 }
 using ui::ThemeProvider;
 
 namespace views {
 
 class DefaultThemeProvider;
 class InputMethod;
 class NativeWidget;
 class NonClientFrameView;
 class ScopedEvent;
-class TooltipManager;
 class View;
 class WidgetDelegate;
 namespace internal {
 class NativeWidgetPrivate;
 class RootView;
 }
 
 ////////////////////////////////////////////////////////////////////////////////
 // Widget class
 //
@@ skipping 670 matching lines @@
   // deliver them. Displaying a window may result in the system generating
   // duplicate move events even though the mouse hasn't moved.
   bool last_mouse_event_was_move_;
   gfx::Point last_mouse_event_position_;
 
   DISALLOW_COPY_AND_ASSIGN(Widget);
 };
 
 }  // namespace views
 
-#endif // VIEWS_WIDGET_WIDGET_H_
+#endif  // VIEWS_WIDGET_WIDGET_H_