DataTransfer: Make |types| be a FrozenArray<DOMString>.

third_party/WebKit/Source/core/clipboard/DataTransfer.h

 /*
  * Copyright (C) 2001 Peter Kelly (pmk@post.com)
  * Copyright (C) 2001 Tobias Anton (anton@stud.fbi.fh-darmstadt.de)
  * Copyright (C) 2006 Samuel Weinig (sam.weinig@gmail.com)
  * Copyright (C) 2003, 2004, 2005, 2006, 2008 Apple Inc. All rights reserved.
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
  * License as published by the Free Software Foundation; either
  * version 2 of the License, or (at your option) any later version.
  *
  * This library is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  * Library General Public License for more details.
  *
  * You should have received a copy of the GNU Library General Public License
  * along with this library; see the file COPYING.LIB.  If not, write to
  * the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
  * Boston, MA 02110-1301, USA.
  *
  */
 
 #ifndef DataTransfer_h
 #define DataTransfer_h
 
 #include <memory>
 #include "core/CoreExport.h"
+#include "core/clipboard/DataObject.h"
 #include "core/clipboard/DataTransferAccessPolicy.h"
 #include "core/loader/resource/ImageResourceContent.h"
 #include "core/page/DragActions.h"
 #include "platform/bindings/ScriptWrappable.h"
 #include "platform/geometry/IntPoint.h"
 #include "platform/heap/Handle.h"
 #include "platform/wtf/Forward.h"
 
 namespace blink {
 
-class DataObject;
 class DataTransferItemList;
 class DragImage;
 class Element;
 class FileList;
 class FrameSelection;
 class LocalFrame;
 class Node;
 
 // Used for drag and drop and copy/paste.
 // Drag and Drop:
 // http://www.whatwg.org/specs/web-apps/current-work/multipage/dnd.html
 // Clipboard API (copy/paste):
 // http://dev.w3.org/2006/webapi/clipops/clipops.html
 class CORE_EXPORT DataTransfer final
     : public GarbageCollectedFinalized<DataTransfer>,
-      public ScriptWrappable {
+      public ScriptWrappable,
+      public DataObject::Observer {
+  USING_GARBAGE_COLLECTED_MIXIN(DataTransfer);
   DEFINE_WRAPPERTYPEINFO();
 
  public:
   // Whether this transfer is serving a drag-drop, copy-paste, spellcheck,
   // auto-correct or similar request.
   enum DataTransferType {
     kCopyAndPaste,
     kDragAndDrop,
     kInsertReplacementText,
   };
@@ skipping 14 matching lines @@
   bool DropEffectIsUninitialized() const {
     return drop_effect_ == "uninitialized";
   }
   String effectAllowed() const { return effect_allowed_; }
   void setEffectAllowed(const String&);
 
   void clearData(const String& type = String());
   String getData(const String& type) const;
   void setData(const String& type, const String& data);
 
-  // extensions beyond IE's API
-  Vector<String> types() const;
+  // Used by the bindings code to determine whether to call types() again.
+  bool hasDataStoreItemListChanged() const;
+
+  Vector<String> types();
   FileList* files() const;
 
   IntPoint DragLocation() const { return drag_loc_; }
   void setDragImage(Element*, int x, int y);
   void ClearDragImage();
   void SetDragImageResource(ImageResourceContent*, const IntPoint&);
   void SetDragImageElement(Node*, const IntPoint&);
 
   std::unique_ptr<DragImage> CreateDragImage(IntPoint& drag_location,
                                              LocalFrame*) const;
@@ skipping 29 matching lines @@
   DECLARE_TRACE();
 
  private:
   DataTransfer(DataTransferType, DataTransferAccessPolicy, DataObject*);
 
   void setDragImage(ImageResourceContent*, Node*, const IntPoint&);
 
   bool HasFileOfType(const String&) const;
   bool HasStringOfType(const String&) const;
 
+  // DataObject::Observer override.
+  void OnItemListChanged();

[jsbell, 2017/05/15 20:49:29]

Mark with `override`

[Raphael Kubo da Costa (rakuco), 2017/05/16 08:51:51]

Done.

+
   // Instead of using this member directly, prefer to use the can*() methods
   // above.
   DataTransferAccessPolicy policy_;
   String drop_effect_;
   String effect_allowed_;
   DataTransferType transfer_type_;
   Member<DataObject> data_object_;
 
+  bool data_store_item_list_changed_;
+
   IntPoint drag_loc_;
   Member<ImageResourceContent> drag_image_;
   Member<Node> drag_image_element_;
 };
 
 DragOperation ConvertDropZoneOperationToDragOperation(
     const String& drag_operation);
 String ConvertDragOperationToDropZoneOperation(DragOperation);
 
 }  // namespace blink
 
 #endif  // DataTransfer_h