Enabled/disable touch screen in TabletPowerButtonController

ash/common/shell_delegate.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_COMMON_SHELL_DELEGATE_H_
 #define ASH_COMMON_SHELL_DELEGATE_H_
 
 #include <memory>
 #include <string>
 
@@ skipping 115 matching lines @@
   // Creates a GPU support object. Shell takes ownership of the object.
   virtual GPUSupport* CreateGPUSupport() = 0;
 
   // Get the product name.
   virtual base::string16 GetProductName() const = 0;
 
   virtual void OpenKeyboardShortcutHelpPage() const {}
 
   virtual gfx::Image GetDeprecatedAcceleratorImage() const = 0;
 
-  // Toggles the status of the touchpad / touchscreen on or off.
+  // If |use_local_state| is true, returns the touchscreen status from local
+  // prefs, otherwise from user prefs.

[Daniel Erat, 2016/12/03 00:08:44]

nit: s/local prefs/local state/

[Qiang(Joe) Xu, 2016/12/03 01:02:44]

Done.

+  virtual bool IsTouchscreenEnabledInPrefs(bool use_local_state) const = 0;
+
+  // Sets the status of touchscreen to |enabled| in prefs. If |use_local_state|,
+  // pref is set in local pref, otherwise in user pref.

[Daniel Erat, 2016/12/03 00:08:44]

nit: s/local pref/local state/, s/user pref/user prefs/

[Qiang(Joe) Xu, 2016/12/03 01:02:44]

Done.

+  virtual void SetTouchscreenEnabledInPrefs(bool enabled,
+                                            bool use_local_state) = 0;
+
+  // Updates the on/off status of the touchscreen from the combination of local

[Daniel Erat, 2016/12/03 00:08:44]

nit: s/local/local state/

i think it'd probably be worthwhile to also document in this comment how the two
possible values interact (i think that both need to be set to true, right?). not
having this documented in the interface is a bit confusing, since one needs to
look at all of the implementations to figure out what the desired behavior is.

[Qiang(Joe) Xu, 2016/12/03 01:02:44]

Done.

+  // and user's preferences.
+  virtual void UpdateTouchscreenStatusFromPrefs() = 0;
+
+  // Toggles the status of the touchpad on or off.
   virtual void ToggleTouchpad() {}
-  virtual void ToggleTouchscreen() {}
 };
 
 }  // namespace ash
 
 #endif  // ASH_COMMON_SHELL_DELEGATE_H_