Get event targetting working for mouse events.

mojo/services/window_manager/view_event_dispatcher.h

 // Copyright 2014 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 MOJO_SERVICES_WINDOW_MANAGER_VIEW_EVENT_DISPATCHER_H_
 #define MOJO_SERVICES_WINDOW_MANAGER_VIEW_EVENT_DISPATCHER_H_
 
 #include "base/memory/scoped_ptr.h"
 #include "ui/events/event_processor.h"
 #include "ui/events/event_target.h"
@@ skipping 14 matching lines @@
   ui::EventTarget* GetRootTarget() override;
   void OnEventProcessingStarted(ui::Event* event) override;
 
   // Overridden from ui::EventDispatcherDelegate.
   bool CanDispatchToTarget(ui::EventTarget* target) override;
   ui::EventDispatchDetails PreDispatchEvent(ui::EventTarget* target,
                                             ui::Event* event) override;
   ui::EventDispatchDetails PostDispatchEvent(
       ui::EventTarget* target, const ui::Event& event) override;
 
-  // We own the root of the shadow tree which mirrors the mojo::View* tree.
-  scoped_ptr<ViewTarget> root_view_target_;
+  // We keep a weak reference to ViewTarget*, which corresponds to the root of
+  // the mojo::View tree.
+  ViewTarget* root_view_target_;
 
   ViewTarget* event_dispatch_target_;
   ViewTarget* old_dispatch_target_;
 
   DISALLOW_COPY_AND_ASSIGN(ViewEventDispatcher);
 };
 
 }  // namespace mojo
 
 #endif  // MOJO_SERVICES_WINDOW_MANAGER_VIEW_EVENT_DISPATCHER_H_