Revert 137549 because it broke win_aura and linux_chromeos_clang compile.

ash/shell.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 ASH_SHELL_H_
 #define ASH_SHELL_H_
 #pragma once
 
 #include <utility>
 #include <vector>
@@ skipping 68 matching lines @@
 class PartialScreenshotEventFilter;
 class ResizeShadowController;
 class RootWindowLayoutManager;
 class ScreenDimmer;
 class ShadowController;
 class ShelfLayoutManager;
 class ShellContextMenu;
 class SystemGestureEventFilter;
 class StackingController;
 class TooltipController;
-class TouchObserverHUD;
 class VisibilityController;
 class WindowModalityController;
 class WorkspaceController;
 }
 
 // Shell is a singleton object that presents the Shell API and implements the
 // RootWindow's delegate interface.
 //
 // Upon creation, the Shell sets itself as the RootWindow's delegate, which
 // takes ownership of the Shell.
@@ skipping 262 matching lines @@
   scoped_ptr<internal::SystemGestureEventFilter> system_gesture_filter_;
 
 #if !defined(OS_MACOSX)
   // An event filter that pre-handles global accelerators.
   scoped_ptr<internal::AcceleratorFilter> accelerator_filter_;
 #endif
 
   // An event filter that pre-handles all key events to send them to an IME.
   scoped_ptr<aura::shared::InputMethodEventFilter> input_method_filter_;
 
-  // An event filter that silently keeps track of all touch events and controls
-  // a heads-up display. This is enabled only if --ash-touch-hud flag is used.
-  scoped_ptr<internal::TouchObserverHUD> touch_observer_hud_;
-
   // The shelf for managing the launcher and the status widget in non-compact
   // mode. Shell does not own the shelf. Instead, it is owned by container of
   // the status area.
   internal::ShelfLayoutManager* shelf_;
 
   // Manages layout of panels. Owned by PanelContainer.
   internal::PanelLayoutManager* panel_layout_manager_;
 
   ObserverList<ShellObserver> observers_;
 
   // Owned by aura::RootWindow, cached here for type safety.
   internal::RootWindowLayoutManager* root_window_layout_;
 
   // System tray with clock, Wi-Fi signal, etc.
   scoped_ptr<SystemTray> tray_;
 
   // Used by ash/shell.
   content::BrowserContext* browser_context_;
 
   DISALLOW_COPY_AND_ASSIGN(Shell);
 };
 
 }  // namespace ash
 
 #endif  // ASH_SHELL_H_