Add support for providing an external file for extracting content.

components/dom_distiller/core/javascript/domdistiller.js

-// 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.
-
-// Applies DomDistillerJs to the content of the page and returns a
-// DomDistillerResults (as a javascript object/dict).
-(function() {
-  try {
-    // The generated domdistiller.js accesses the window object only explicitly
-    // via the window name. So, we create a new object with the normal window
-    // object as its prototype and initialize the domdistiller.js with that new
-    // context so that it doesn't change the real window object.
-    function initialize(window) {
-      // This include will be processed at build time by grit.
-      <include src="../../../../third_party/dom_distiller_js/package/js/domdistiller.js"/>
-    }
-    var context = Object.create(window);
-    context.setTimeout = function() {};
-    context.clearTimeout = function() {};
-    initialize(context);
-
-    // The OPTIONS placeholder will be replaced with the DomDistillerOptions at
-    // runtime.
-    var distiller = context.org.chromium.distiller.DomDistiller;
-    var res = distiller.applyWithOptions($$OPTIONS);
-    return res;
-  } catch (e) {
-    window.console.error("Error during distillation: " + e);
-    if (e.stack != undefined) window.console.error(e.stack);
-  }
-  return undefined;
-})()