aura: Start converting event-filters into event-handlers.

ui/base/events/event_target.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_BASE_EVENTS_EVENT_TARGET_H_
 #define UI_BASE_EVENTS_EVENT_TARGET_H_
 
 #include "base/compiler_specific.h"
 #include "ui/base/events/event_handler.h"
 #include "ui/base/ui_export.h"
@@ skipping 14 matching lines @@
       return target_->pre_target_list_;
     }
 
    private:
     TestApi();
     EventTarget* target_;
 
     DISALLOW_COPY_AND_ASSIGN(TestApi);
   };
 
+  class DispatcherApi {
+   public:
+    explicit DispatcherApi(EventTarget* target) : target_(target) {}
+
+    const EventHandlerList& pre_target_list() const {
+      return target_->pre_target_list_;
+    }
+
+   private:
+    DispatcherApi();
+    EventTarget* target_;
+
+    DISALLOW_COPY_AND_ASSIGN(DispatcherApi);
+  };
+
   EventTarget();
   virtual ~EventTarget();
 
   virtual bool CanAcceptEvents() = 0;
   virtual EventTarget* GetParentTarget() = 0;
 
   // Adds a handler to receive events before the target. The handler must be
   // explicitly removed from the target before the handler is destroyed. The
   // EventTarget does not take ownership of the handler.
   void AddPreTargetHandler(EventHandler* handler);
@@ skipping 33 matching lines @@
   EventHandlerList pre_target_list_;
   EventHandlerList post_target_list_;
   EventHandler* target_handler_;
 
   DISALLOW_COPY_AND_ASSIGN(EventTarget);
 };
 
 }  // namespace ui
 
 #endif  // UI_BASE_EVENTS_EVENT_TARGET_H_