Enabled/disable touch screen in TabletPowerButtonController

ash/common/shell_delegate.h

Index: ash/common/shell_delegate.h
diff --git a/ash/common/shell_delegate.h b/ash/common/shell_delegate.h
index 27d59cff49f0f1b6b4e3b1e0bf4625e1c04a92fe..f86947fc26e4029ccfba0d9e23fd3ddc2a10b37a 100644
--- a/ash/common/shell_delegate.h
+++ b/ash/common/shell_delegate.h
@@ -133,9 +133,21 @@ class ASH_EXPORT ShellDelegate {
 
   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