Add support for providing an external file for extracting content.

components/dom_distiller/ios/distiller_page_ios.mm

Index: components/dom_distiller/ios/distiller_page_ios.mm
diff --git a/components/dom_distiller/ios/distiller_page_ios.mm b/components/dom_distiller/ios/distiller_page_ios.mm
index 4d04aa66a24c55cc5a4a188aa785d7a9edbe5b6e..08d5156a07188819c225eb7f374f0ffe51151f06 100644
--- a/components/dom_distiller/ios/distiller_page_ios.mm
+++ b/components/dom_distiller/ios/distiller_page_ios.mm
@@ -44,8 +44,11 @@ void DistillerWebStateObserver::PageLoaded(
 
 #pragma mark -
 
-DistillerPageIOS::DistillerPageIOS(web::BrowserState* browser_state)
-    : browser_state_(browser_state), weak_ptr_factory_(this) {
+DistillerPageIOS::DistillerPageIOS(web::BrowserState* browser_state,
+                                   const std::string& distiller_js_script)
+    : DistillerPage(distiller_js_script),
+      browser_state_(browser_state),
+      weak_ptr_factory_(this) {
 }
 
 DistillerPageIOS::~DistillerPageIOS() {