Add GetOriginalRequestURL() to NavigationItem interface.

ios/web/navigation/navigation_item_impl.h

Index: ios/web/navigation/navigation_item_impl.h
diff --git a/ios/web/navigation/navigation_item_impl.h b/ios/web/navigation/navigation_item_impl.h
index 2d58a968c6097107d4ee787c9832aaf3be4d8e6d..8613c3b59e510632e36d23e05b00f4a4826b3dcc 100644
--- a/ios/web/navigation/navigation_item_impl.h
+++ b/ios/web/navigation/navigation_item_impl.h
@@ -42,6 +42,8 @@ class NavigationItemImpl : public web::NavigationItem {
 
   // NavigationItem implementation:
   int GetUniqueID() const override;
+  void SetOriginalRequestURL(const GURL& url) override;
+  const GURL& GetOriginalRequestURL() const override;
   void SetURL(const GURL& url) override;
   const GURL& GetURL() const override;
   void SetReferrer(const web::Referrer& referrer) override;
@@ -119,6 +121,7 @@ class NavigationItemImpl : public web::NavigationItem {
 
  private:
   int unique_id_;
+  GURL original_request_url_;
   GURL url_;
   Referrer referrer_;
   GURL virtual_url_;