Enabled/disable touch screen in TabletPowerButtonController

ash/shell/shell_delegate_impl.h

Index: ash/shell/shell_delegate_impl.h
diff --git a/ash/shell/shell_delegate_impl.h b/ash/shell/shell_delegate_impl.h
index 073d3669902187316eab76f3f1ff24967b392185..590da661fefe4526f237f698f64be666ac2ed1dc 100644
--- a/ash/shell/shell_delegate_impl.h
+++ b/ash/shell/shell_delegate_impl.h
@@ -53,6 +53,10 @@ class ShellDelegateImpl : public ShellDelegate {
   GPUSupport* CreateGPUSupport() override;
   base::string16 GetProductName() const override;
   gfx::Image GetDeprecatedAcceleratorImage() const override;
+  bool IsTouchscreenEnabledInPrefs(bool use_local_state) const override;
+  void SetTouchscreenEnabledInPrefs(bool enabled,
+                                    bool use_local_state) override;
+  void UpdateTouchscreenStatusFromPrefs() override;
 
  private:
   ShelfDelegate* shelf_delegate_;