Support targeting for gestures in ViewTargeter

ui/views/widget/root_view.h

Index: ui/views/widget/root_view.h
diff --git a/ui/views/widget/root_view.h b/ui/views/widget/root_view.h
index 97ce1d5cb2cbbc157b093dc482b30ac941528540..533d69bd875dfe6db4d2c452539e622fef74a24d 100644
--- a/ui/views/widget/root_view.h
+++ b/ui/views/widget/root_view.h
@@ -17,9 +17,11 @@
 namespace views {
 
 namespace test {
+class ViewTargeterTest;
 class WidgetTest;
 }
 
+class ViewTargeter;
 class Widget;
 
 // This is a views-internal API and should not be used externally.
@@ -123,7 +125,9 @@ class VIEWS_EXPORT RootView : public View,
 
  private:
   friend class ::views::View;
+  friend class ::views::ViewTargeter;
   friend class ::views::Widget;
+  friend class ::views::test::ViewTargeterTest;
   friend class ::views::test::WidgetTest;
 
   // Input ---------------------------------------------------------------------
@@ -187,10 +191,13 @@ class VIEWS_EXPORT RootView : public View,
   int last_mouse_event_x_;
   int last_mouse_event_y_;
 
-  // The view currently handling gesture events. When set, this handler receives
-  // all gesture events.
+  // The View currently handling gesture events.
   View* gesture_handler_;
 
+  // If true, then gesture events received from Widget should be dispatched to
+  // |gesture_handler_|.
+  bool dispatch_to_gesture_handler_;

[tdanderson, 2014/08/16 20:34:23]

I admit that introducing this member does feel a bit clumsy and it would be
really nice if it could be avoided. But it seems this is necessary because it
keeps track of information which is currently (implicitly) tracked by
RootView::DispatchGestureEvent()'s soon-to-be-removed loops. That is, we know
whether or not |gesture_handler_| was established by a previous gesture event
simply by which loop we're inside in DispatchGestureEvent().

+
   scoped_ptr<internal::PreEventDispatchHandler> pre_dispatch_handler_;
   scoped_ptr<internal::PostEventDispatchHandler> post_dispatch_handler_;