Don't allow drop to panels (pop-ups) in ChromeOS.

chrome/browser/tab_contents/tab_contents.h

 // Copyright (c) 2010 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_TAB_CONTENTS_H_
 #define CHROME_BROWSER_TAB_CONTENTS_TAB_CONTENTS_H_
 
 #include "build/build_config.h"
 
 #include <deque>
@@ skipping 649 matching lines @@
     request_context_ = context;
   }
   URLRequestContextGetter* request_context() const {
     return request_context_.get();
   }
 
   LanguageState& language_state() {
     return language_state_;
   }
 
+  // Returns true if underlying TabContentsView should accept drag-n-drop.
+  bool ShouldAcceptDragAndDrop() const;
+
   // Creates a duplicate of this TabContents. The returned TabContents is
   // configured such that the renderer has not been loaded (it'll load the first
   // time it is selected).
   // This is intended for use with apps.
   // The caller owns the returned object.
   TabContents* CloneAndMakePhantom();
 
   // Indicates if this tab was explicitly closed by the user (control-w, close
   // tab menu item...). This is false for actions that indirectly close the tab,
   // such as closing the window.  The setter is maintained by TabStripModel, and
@@ skipping 610 matching lines @@
 
   // See description above setter.
   bool closed_by_user_gesture_;
 
   // ---------------------------------------------------------------------------
 
   DISALLOW_COPY_AND_ASSIGN(TabContents);
 };
 
 #endif  // CHROME_BROWSER_TAB_CONTENTS_TAB_CONTENTS_H_