gfx: Make conversions from gfx::Point to PointF explicit.

ui/base/dragdrop/drop_target_event.h

 // Copyright (c) 2013 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_DRAGDROP_DROP_TARGET_EVENT_H_
 #define UI_BASE_DRAGDROP_DROP_TARGET_EVENT_H_
 
 #include "ui/events/event.h"
 #include "ui/base/dragdrop/os_exchange_data.h"
 
 namespace ui {
 
 class UI_BASE_EXPORT DropTargetEvent : public LocatedEvent {
  public:
   DropTargetEvent(const OSExchangeData& data,
-                  const gfx::PointF& location,
-                  const gfx::PointF& root_location,
+                  const gfx::Point& location,
+                  const gfx::Point& root_location,
                   int source_operations);
 
   const OSExchangeData& data() const { return data_; }
   int source_operations() const { return source_operations_; }
 
  private:
   // Data associated with the drag/drop session.
   const OSExchangeData& data_;
 
   // Bitmask of supported DragDropTypes::DragOperation by the source.
   int source_operations_;
 
   DISALLOW_COPY_AND_ASSIGN(DropTargetEvent);
 };
 
 }  // namespace ui
 
 #endif  // UI_BASE_DRAGDROP_DROP_TARGET_EVENT_H_