Cleanup: Remove unneeded forward declarations in views.

views/widget/native_widget_gtk.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_NATIVE_WIDGET_GTK_H_
 #define VIEWS_WIDGET_NATIVE_WIDGET_GTK_H_
 #pragma once
 
 #include <gtk/gtk.h>
 
@@ skipping 17 matching lines @@
 class OSExchangeDataProviderGtk;
 class GtkSignalRegistrar;
 }
 using ui::OSExchangeData;
 using ui::OSExchangeDataProviderGtk;
 
 namespace views {
 
 class DropTargetGtk;
 class InputMethod;
-class TooltipManagerGtk;
 class View;
 
 namespace internal {
 class NativeWidgetDelegate;
 }
 
 // Widget implementation for GTK.
 class VIEWS_EXPORT NativeWidgetGtk : public internal::NativeWidgetPrivate,
                                      public ui::CompositorDelegate,
                                      public ui::ActiveWindowWatcherX::Observer {
@@ skipping 418 matching lines @@
   bool is_menu_;
 
   scoped_ptr<ui::GtkSignalRegistrar> signal_registrar_;
 
   DISALLOW_COPY_AND_ASSIGN(NativeWidgetGtk);
 };
 
 }  // namespace views
 
 #endif  // VIEWS_WIDGET_NATIVE_WIDGET_GTK_H_