Enable touch-initiated drag-drop work on Windows

content/browser/web_contents/web_contents_drag_win.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 CONTENT_BROWSER_WEB_CONTENTS_WEB_CONTENTS_DRAG_WIN_H_
 #define CONTENT_BROWSER_WEB_CONTENTS_WEB_CONTENTS_DRAG_WIN_H_
 
 #include "base/callback.h"
 #include "base/compiler_specific.h"
 #include "base/memory/ref_counted.h"
@@ skipping 70 matching lines @@
   void StartBackgroundDragging(const WebDropData& drop_data,
                                WebKit::WebDragOperationsMask ops,
                                const GURL& page_url,
                                const std::string& page_encoding,
                                const gfx::ImageSkia& image,
                                const gfx::Vector2d& image_offset);
   // Called on UI thread.
   void EndDragging();
   void CloseThread();
 
+
+  // Programmatically send mouse down event for touch-initiated drag and drop.
+  void SendMouseEventForTouchDnD();
+
   // For debug check only. Access only on drag-and-drop thread.
   base::PlatformThreadId drag_drop_thread_id_;
 
   // All the member variables below are accessed on UI thread.
 
   gfx::NativeWindow source_window_;
   WebContents* web_contents_;
   WebDragDest* drag_dest_;
 
   // |drag_source_| is our callback interface passed to the system when we
   // want to initiate a drag and drop operation.  We use it to tell if a
   // drag operation is happening.
   scoped_refptr<WebDragSource> drag_source_;
 
   // The thread used by the drag-out download. This is because we want to avoid
   // running nested message loop in main UI thread.
   scoped_ptr<DragDropThread> drag_drop_thread_;
 
   // The flag to guard that EndDragging is not called twice.
   bool drag_ended_;
 
   base::Callback<void()> drag_end_callback_;
 
   DISALLOW_COPY_AND_ASSIGN(WebContentsDragWin);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_BROWSER_WEB_CONTENTS_WEB_CONTENTS_DRAG_WIN_H_