Add support for providing an external file for extracting content.

components/dom_distiller/ios/distiller_page_factory_ios.h

Index: components/dom_distiller/ios/distiller_page_factory_ios.h
diff --git a/components/dom_distiller/ios/distiller_page_factory_ios.h b/components/dom_distiller/ios/distiller_page_factory_ios.h
index ae7f418d37b75e45776abe1e03163cd2763952d4..e0b7fe29aad4c8a8e438731f3ca4c4de7321e56e 100644
--- a/components/dom_distiller/ios/distiller_page_factory_ios.h
+++ b/components/dom_distiller/ios/distiller_page_factory_ios.h
@@ -21,7 +21,8 @@ class DistillerPageIOS;
 // 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(
@@ -31,6 +32,12 @@ class DistillerPageFactoryIOS : public DistillerPageFactory {
 
  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