Add support for providing an external file for extracting content.

components/dom_distiller/core/distiller_page.h

Index: components/dom_distiller/core/distiller_page.h
diff --git a/components/dom_distiller/core/distiller_page.h b/components/dom_distiller/core/distiller_page.h
index 74cf277935b81809bb979aae01e37bac2aa2a2d0..ebe35b500c36801f54b0884214f5fdbfbde0d1aa 100644
--- a/components/dom_distiller/core/distiller_page.h
+++ b/components/dom_distiller/core/distiller_page.h
@@ -33,7 +33,10 @@ class DistillerPage {
       void(scoped_ptr<proto::DomDistillerResult> distilled_page,
            bool distillation_successful)> DistillerPageCallback;
 
-  DistillerPage();
+  // The passed in JavaScript should contain the string $$OPTIONS, which will be
+  // replaced with options passed in as proto::DomDistillerOptions before it is
+  // executed in the page context.
+  explicit DistillerPage(const std::string& distiller_js_script);
   virtual ~DistillerPage();
 
   // Loads a URL. |OnDistillationDone| is called when the load completes or
@@ -51,13 +54,21 @@ class DistillerPage {
 
  protected:
   // Called by |DistillPage| to carry out platform-specific instructions to load
-  // and distill the |url| using the provided |script|. The extracted content
-  // should be the same regardless of the DistillerPage implementation.
+  // and distill the |url|. The extracted content should be the same regardless
+  // of the DistillerPage implementation.
   virtual void DistillPageImpl(const GURL& url, const std::string& script) = 0;

[noyau (Ping after 24h), 2015/03/11 14:30:59]

The comment should specify that the options have been replaced in the passed on
script.

 
  private:
   bool ready_;
+
+  // Contains the script which will be injected into the page which is
+  // being distilled.  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_;
+
   DistillerPageCallback distiller_page_callback_;
+
   DISALLOW_COPY_AND_ASSIGN(DistillerPage);
 };