Removes some dead code

ash/shell.cc

 // 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.
 
 #include "ash/shell.h"
 
 #include <algorithm>
 #include <string>
 #include <utility>
 
@@ skipping 74 matching lines @@
 #include "ui/aura/window.h"
 #include "ui/aura/window_event_dispatcher.h"
 #include "ui/base/ui_base_switches.h"
 #include "ui/base/user_activity/user_activity_detector.h"
 #include "ui/compositor/layer.h"
 #include "ui/compositor/layer_animator.h"
 #include "ui/display/display.h"
 #include "ui/display/manager/display_manager.h"
 #include "ui/display/screen.h"
 #include "ui/events/event_target_iterator.h"
-#include "ui/gfx/geometry/size.h"
+#include "ui/gfx/geometry/insets.h"
 #include "ui/gfx/image/image_skia.h"
 #include "ui/keyboard/keyboard_controller.h"
 #include "ui/keyboard/keyboard_switches.h"
 #include "ui/keyboard/keyboard_util.h"
 #include "ui/message_center/message_center.h"
 #include "ui/views/corewm/tooltip_aura.h"
 #include "ui/views/corewm/tooltip_controller.h"
 #include "ui/views/widget/native_widget_aura.h"
 #include "ui/views/widget/widget.h"
 #include "ui/wm/core/accelerator_filter.h"
@@ skipping 802 matching lines @@
 std::unique_ptr<ui::EventTargetIterator> Shell::GetChildIterator() const {
   return std::unique_ptr<ui::EventTargetIterator>();
 }
 
 ui::EventTargeter* Shell::GetEventTargeter() {
   NOTREACHED();
   return nullptr;
 }
 
 }  // namespace ash