Implement chrome.streamsPrivate.abort() extensions function

chrome/common/extensions/api/streams_private.idl

 // Copyright 2014 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.
 
 // Streams Private API.
 namespace streamsPrivate {
   dictionary StreamInfo {
     // The MIME type of the intercepted URL request.
     DOMString mimeType;
 
@@ skipping 11 matching lines @@
     // information on the size it will be -1.
     long expectedContentSize;
 
     // The HTTP response headers of the intercepted request stored as a
     // dictionary mapping header name to header value. If a header name appears
     // multiple times, the header values are merged in the dictionary and
     // separated by a ", ".
     object responseHeaders;
   };
 
+  interface Functions {
+    // Abort the URL request on the given stream.
+    // |streamUrl| : The URL of the stream to abort.
+    static void abort(DOMString streamUrl);
+  };
+
   interface Events {
     // Fired when a resource is fetched which matches a mime type handled by
     // this extension. The resource request is cancelled, and the extension is
     // expected to handle the request. The event is restricted to a small number
     // of white-listed extensions.
     static void onExecuteMimeTypeHandler(StreamInfo streamInfo);
   };
 };