touch: Return an enum from OnTouchEvent.

views/view.h

Index: views/view.h
diff --git a/views/view.h b/views/view.h
index 3c77e03aaf1536b4a6dc88c1a7544016ecd39239..6889a7fe83775e2a3559617a7e9b2c28a644d0f0 100644
--- a/views/view.h
+++ b/views/view.h
@@ -78,7 +78,6 @@ class ContextMenuController {
 // DragController is responsible for writing drag data for a view, as well as
 // supplying the supported drag operations. Use DragController if you don't
 // want to subclass.
-
 class DragController {
  public:
   // Writes the data for the drag.
@@ -101,6 +100,16 @@ class DragController {
   virtual ~DragController() {}
 };
 
+#if defined(TOUCH_UI)
+// TouchEventObserver observes the touch event for the completion of a touch
+// sequence.
+class TouchEventObserver {
+ public:
+  // Invoked when a touch sequence ends.
+   virtual void OnTouchSequenceEnd() = 0;
+};
+#endif
+
 /////////////////////////////////////////////////////////////////////////////
 //
 // View class
@@ -1119,6 +1128,12 @@ class View : public AcceleratorTarget {
   // even though it may not be normally focusable.
   bool accessibility_focusable_;
 
+#if defined(TOUCH_UI)
+  // The touch event handler should notify the observer when a touch-sequence
+  // completely ends.
+  TouchEventObserver* touch_event_observer_;
+#endif
+
  private:
   friend class RootView;
   friend class FocusManager;
@@ -1162,6 +1177,11 @@ class View : public AcceleratorTarget {
   // the result of OnTouchEvent: true if the event was handled by the
   // callee.
   bool ProcessTouchEvent(const TouchEvent& e);
+
+  // Set the touch event observer.
+  void set_touch_event_observer(TouchEventObserver* observer) {
+    touch_event_observer_ = observer;
+  }
 #endif
 
   // Starts a drag and drop operation originating from this view. This invokes