Extract touchscreen device management into a generic manager

ash/shell.h

Index: ash/shell.h
diff --git a/ash/shell.h b/ash/shell.h
index 354d653c7aa14ffa557d81fd467d1eaea80d2341..66be2183facb473f014606c6a00f26ac059ce518 100644
--- a/ash/shell.h
+++ b/ash/shell.h
@@ -375,11 +375,11 @@ class ASH_EXPORT Shell : public SystemModalContainerEventFilterDelegate,
   DisplayController* display_controller() {
     return display_controller_.get();
   }
-#if defined(OS_CHROMEOS) && defined(USE_X11)
+#if defined(OS_CHROMEOS)
   TouchTransformerController* touch_transformer_controller() {
     return touch_transformer_controller_.get();
   }
-#endif  // defined(OS_CHROMEOS) && defined(USE_X11)
+#endif  // defined(OS_CHROMEOS)
   MouseCursorEventFilter* mouse_cursor_filter() {
     return mouse_cursor_filter_.get();
   }
@@ -721,11 +721,11 @@ class ASH_EXPORT Shell : public SystemModalContainerEventFilterDelegate,
 
   // Listens for output changes and updates the display manager.
   scoped_ptr<DisplayChangeObserver> display_change_observer_;
+  scoped_ptr<TouchTransformerController> touch_transformer_controller_;
 
 #if defined(USE_X11)
   scoped_ptr<ui::EventHandler> magnifier_key_scroll_handler_;
   scoped_ptr<ui::EventHandler> speech_feedback_handler_;
-  scoped_ptr<TouchTransformerController> touch_transformer_controller_;
 #endif  // defined(USE_X11)
 #endif  // defined(OS_CHROMEOS)