Add support for providing an external file for extracting content.

components/dom_distiller/ios/distiller_page_factory_ios.h

 // Copyright 2015 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 COMPONENTS_DOM_DISTILLER_IOS_DISTILLER_PAGE_FACTORY_IOS_H_
 #define COMPONENTS_DOM_DISTILLER_IOS_DISTILLER_PAGE_FACTORY_IOS_H_
 
 #include "base/memory/scoped_ptr.h"
 #include "components/dom_distiller/core/distiller_page.h"
 
 namespace web {
 class BrowserState;
 }
 
 namespace dom_distiller {
 
 class DistillerPageIOS;
 
 // DistillerPageFactoryIOS is an iOS-specific implementation of the
 // DistillerPageFactory interface allowing the creation of DistillerPage
 // instances.
 class DistillerPageFactoryIOS : public DistillerPageFactory {
  public:
-  DistillerPageFactoryIOS(web::BrowserState* browser_state);
+  DistillerPageFactoryIOS(web::BrowserState* browser_state,
+                          const std::string& distiller_js_script);
 
   // Implementation of DistillerPageFactory:
   scoped_ptr<DistillerPage> CreateDistillerPage(
       const gfx::Size& view_size) const override;
   scoped_ptr<DistillerPage> CreateDistillerPageWithHandle(
       scoped_ptr<SourcePageHandle> handle) const override;
 
  private:
   web::BrowserState* browser_state_;
+
+  // Contains the script which will be passed on when constructing the
+  // DistillerPageIOS. It should contain the string $$OPTIONS, which
+  // will be replaced with options passed in as proto::DomDistillerOptions
+  // before it is executed in the page context.
+  std::string distiller_js_script_;
 };
 
 }  // namespace dom_distiller
 
 #endif  // COMPONENTS_DOM_DISTILLER_IOS_DISTILLER_PAGE_FACTORY_IOS_H_