aura: Fix a couple of bug (really the same bug at two different places) for drag

content/browser/web_contents/web_contents_view_aura.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_VIEW_AURA_H_
 #define CONTENT_BROWSER_WEB_CONTENTS_WEB_CONTENTS_VIEW_AURA_H_
 #pragma once
 
 #include "base/memory/ref_counted.h"
 #include "base/memory/scoped_ptr.h"
@@ skipping 120 matching lines @@
   WebContentsViewHelper web_contents_view_helper_;
 
   WebKit::WebDragOperationsMask current_drag_op_;
 
   // Set to true if we want to close the tab after the system drag operation
   // has finished.
   bool close_tab_after_drag_ends_;
 
   content::WebDragDestDelegate* drag_dest_delegate_;
 
+  // We keep track of the render view host we're dragging over.  If it changes
+  // during a drag, we need to re-send the DragEnter message.  WARNING:
+  // this pointer should never be dereferenced.  We only use it for comparing
+  // pointers.
+  void* current_rvh_for_drag_;
+
   DISALLOW_COPY_AND_ASSIGN(WebContentsViewAura);
 };
 
 #endif  // CONTENT_BROWSER_WEB_CONTENTS_WEB_CONTENTS_VIEW_AURA_H_