Move chrome.downloads out of experimental to dev

chrome/common/extensions/api/experimental_discovery.idl

 // 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.
 
-// File-level comment to appease parser. Eventually this will not be necessary.
-
 namespace experimental.discovery {
 
   dictionary SuggestDetails {
     // The URL to suggest and that will be displayed in the new tab page under
     // the recommended pane.
     DOMString linkUrl;
 
     // The linkified text. It should be relatively short.
     DOMString linkText;
 
@@ skipping 12 matching lines @@
     // Removes a URL that was previously suggested for discovery by this
     // extension.
     // |linkUrl|: The URl to remove from discovery. Must be exactly the same as
     // a linkUrl previously used on a call to suggest.
     static void removeSuggestion(DOMString linkUrl);
 
     // Clear all the URLs that were previously suggested for discovery by this
     // extension.
     static void clearAllSuggestions();
   };
-};
+};