Remove window/host accessors from WED; IWYU for WTH

ui/views/corewm/tooltip_aura.cc

 // Copyright 2013 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.
 
 #include "ui/views/corewm/tooltip_aura.h"
 
 #include "base/command_line.h"
 #include "base/strings/string_split.h"
 #include "ui/aura/window.h"
-#include "ui/aura/window_event_dispatcher.h"
+#include "ui/aura/window_tree_host.h"
 #include "ui/base/resource/resource_bundle.h"
 #include "ui/gfx/screen.h"
 #include "ui/gfx/text_elider.h"
 #include "ui/gfx/text_utils.h"
 #include "ui/views/background.h"
 #include "ui/views/border.h"
 #include "ui/views/widget/widget.h"
 
 namespace {
 
@@ skipping 232 matching lines @@
 }
 
 void TooltipAura::OnWidgetDestroying(views::Widget* widget) {
   DCHECK_EQ(widget_, widget);
   widget_ = NULL;
   tooltip_window_ = NULL;
 }
 
 }  // namespace corewm
 }  // namespace views