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

chrome/browser/tab_contents/tab_contents.h

Index: chrome/browser/tab_contents/tab_contents.h
diff --git a/chrome/browser/tab_contents/tab_contents.h b/chrome/browser/tab_contents/tab_contents.h
index 5d491072e0c39e5008d269332cc1b55e2f72721b..42c409b449a3f2ce739f0a55f6c0d2e27271a858 100644
--- a/chrome/browser/tab_contents/tab_contents.h
+++ b/chrome/browser/tab_contents/tab_contents.h
@@ -667,6 +667,9 @@ class TabContents : public PageNavigator,
     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).