Introduce View::CanProcessEventsWithinSubtree()

ui/views/view.h

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef UI_VIEWS_VIEW_H_
 #define UI_VIEWS_VIEW_H_
 
 #include <algorithm>
 #include <map>
 #include <set>
@@ skipping 583 matching lines @@
   //                   their logic is moved into ViewTargeter and its
   //                   derived classes. See crbug.com/355425.
 
   // A convenience function which calls HitTestRect() with a rect of size
   // 1x1 and an origin of |point|.
   bool HitTestPoint(const gfx::Point& point) const;
 
   // Tests whether |rect| intersects this view's bounds.
   virtual bool HitTestRect(const gfx::Rect& rect) const;
 
+  // Returns true if this view or any of its descendants are permitted to
+  // be the target of an event.
+  virtual bool CanProcessEventsWithinSubtree() const;
+
   // Returns true if the mouse cursor is over |view| and mouse events are
   // enabled.
   bool IsMouseHovered();
 
   // This method is invoked when the user clicks on this view.
   // The provided event is in the receiver's coordinate system.
   //
   // Return true if you processed the event and want to receive subsequent
   // MouseDraggged and MouseReleased events.  This also stops the event from
   // bubbling.  If you return false, the event will bubble through parent
@@ skipping 993 matching lines @@
   // Belongs to this view, but it's reference-counted on some platforms
   // so we can't use a scoped_ptr. It's dereferenced in the destructor.
   NativeViewAccessibility* native_view_accessibility_;
 
   DISALLOW_COPY_AND_ASSIGN(View);
 };
 
 }  // namespace views
 
 #endif  // UI_VIEWS_VIEW_H_