Make web_drag_source.cc compile on Posix.

chrome/browser/tab_contents/web_drag_source.h

 // Copyright (c) 2006-2008 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 CHROME_BROWSER_TAB_CONTENTS_WEB_DRAG_SOURCE_H_
 #define CHROME_BROWSER_TAB_CONTENTS_WEB_DRAG_SOURCE_H_
 
+#include "base/basictypes.h"
+#include "base/gfx/native_widget_types.h"
+#include "base/gfx/point.h"
+
+// TODO(port): Port this file.
+#if defined(OS_WIN)
 #include "base/base_drag_source.h"
-#include "base/basictypes.h"
+#else
+#include "chrome/common/temp_scaffolding_stubs.h"
+#endif
 
 class RenderViewHost;
 
 ///////////////////////////////////////////////////////////////////////////////
 //
 // WebDragSource
 //
 //  An IDropSource implementation for a WebContents. Handles notifications sent
 //  by an active drag-drop operation as the user mouses over other drop targets
 //  on their system. This object tells Windows whether or not the drag should
 //  continue, and supplies the appropriate cursors.
 //
 class WebDragSource : public BaseDragSource {
  public:
   // Create a new DragSource for a given HWND and RenderViewHost.
-  WebDragSource(HWND source_hwnd, RenderViewHost* render_view_host);
+  WebDragSource(gfx::NativeWindow source_wnd, RenderViewHost* render_view_host);
   virtual ~WebDragSource() { }
 
  protected:
   // BaseDragSource
   virtual void OnDragSourceDrop();
   virtual void OnDragSourceMove();
 
  private:
   // Cannot construct thusly.
   WebDragSource();
 
-  // Keep a reference to the HWND so we can translate the cursor position.
-  HWND source_hwnd_;
+  // Keep a reference to the window so we can translate the cursor position.
+  gfx::NativeWindow source_wnd_;
 
   // We use this as a channel to the renderer to tell it about various drag
   // drop events that it needs to know about (such as when a drag operation it
   // initiated terminates).
   RenderViewHost* render_view_host_;
 
   DISALLOW_COPY_AND_ASSIGN(WebDragSource);
 };
 
 #endif  // #ifndef CHROME_BROWSER_TAB_CONTENTS_WEB_DRAG_SOURCE_H_