Revert 137549 because it broke win_aura and linux_chromeos_clang compile.

ash/ash_switches.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/ash_switches.h"
 
 namespace ash {
 namespace switches {
 
 // Enables the Oak tree viewer.
 const char kAshEnableOak[] = "ash-enable-oak";
 
 // Use Ash notifications.
 const char kAshNotify[] = "ash-notify";
 
-// Enables the heads-up display for tracking touch points.
-const char kAshTouchHud[] = "ash-touch-hud";
-
 // Use Google-style dialog box frames.
 const char kAuraGoogleDialogFrames[] = "aura-google-dialog-frames";
 
 // (Most) Chrome OS hardware reports ACPI power button releases correctly.
 // Standard hardware reports releases immediately after presses.  If set, we
 // lock the screen or shutdown the system immediately in response to a press
 // instead of displaying an interactive animation.
 const char kAuraLegacyPowerButton[] = "aura-legacy-power-button";
 
 // Avoid drawing drop shadows under windows.
 const char kAuraNoShadows[] = "aura-no-shadows";
 
 // Use Aura to manage windows of type WINDOW_TYPE_PANEL.
 const char kAuraPanelManager[] = "aura-panels";
 
 // If present animations are disabled.
 const char kAuraWindowAnimationsDisabled[] = "aura-window-animations-disabled";
 
 // Enables applist v2.
 const char kEnableAppListV2[] = "enable-applist-v2";
 
 }  // namespace switches
 }  // namespace ash