Move more dnd related files to ui/base

ui/base/dragdrop/drag_source.cc

-// Copyright (c) 2010 The Chromium Authors. All rights reserved.
+// Copyright (c) 2011 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.
 
-#include "app/win/drag_source.h"
+#include "ui/base/dragdrop/drag_source.h"
 
-namespace app {
-namespace win {
+namespace ui {
 
 DragSource::DragSource() : cancel_drag_(false) {
 }
 
 HRESULT DragSource::QueryContinueDrag(BOOL escape_pressed, DWORD key_state) {
   if (cancel_drag_)
     return DRAGDROP_S_CANCEL;
 
   if (escape_pressed) {
     OnDragSourceCancel();
@@ skipping 27 matching lines @@
 ULONG DragSource::AddRef() {
   base::RefCountedThreadSafe<DragSource>::AddRef();
   return 0;
 }
 
 ULONG DragSource::Release() {
   base::RefCountedThreadSafe<DragSource>::Release();
   return 0;
 }
 
-}  // namespace win
-}  // namespace app
+}  // namespace ui