Add support for providing an external file for extracting content.

components/dom_distiller/content/distiller_page_web_contents.h

Index: components/dom_distiller/content/distiller_page_web_contents.h
diff --git a/components/dom_distiller/content/distiller_page_web_contents.h b/components/dom_distiller/content/distiller_page_web_contents.h
index e73b0ccc9b04e5780664768f3189e76507e171b6..c4dc9f421a3d37b63dbcaca7cf0b7dfe5ff6105c 100644
--- a/components/dom_distiller/content/distiller_page_web_contents.h
+++ b/components/dom_distiller/content/distiller_page_web_contents.h
@@ -31,9 +31,8 @@ class SourcePageHandleWebContents : public SourcePageHandle {
 
 class DistillerPageWebContentsFactory : public DistillerPageFactory {
  public:
-  explicit DistillerPageWebContentsFactory(
-      content::BrowserContext* browser_context)
-      : DistillerPageFactory(), browser_context_(browser_context) {}
+  DistillerPageWebContentsFactory(content::BrowserContext* browser_context,
+                                  const std::string& distiller_js_script);
   ~DistillerPageWebContentsFactory() override {}
 
   scoped_ptr<DistillerPage> CreateDistillerPage(
@@ -43,6 +42,11 @@ class DistillerPageWebContentsFactory : public DistillerPageFactory {
 
  private:
   content::BrowserContext* browser_context_;
+  // Contains the script which will be passed on when constructing the
+  // DistillerPageWebContents. 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_;
 };
 
 class DistillerPageWebContents : public DistillerPage,
@@ -52,6 +56,7 @@ class DistillerPageWebContents : public DistillerPage,
   DistillerPageWebContents(
       content::BrowserContext* browser_context,
       const gfx::Size& render_view_size,
+      const std::string& distiller_js_script,
       scoped_ptr<SourcePageHandleWebContents> optional_web_contents_handle);
   ~DistillerPageWebContents() override;