Update from https://crrev.com/306655

url/gurl.h

 // Copyright 2013 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef URL_GURL_H_
 #define URL_GURL_H_
 
 #include <iosfwd>
 #include <string>
 
@@ skipping 180 matching lines @@
   // this URL is not a standard URL, then the result will be an empty,
   // invalid GURL. If the URL has neither username nor password, this
   // degenerates to GetWithEmptyPath().
   //
   // It is an error to get the origin of an invalid URL. The result
   // will be the empty URL.
   GURL GetOrigin() const;
 
   // A helper function to return a GURL stripped from the elements that are not
   // supposed to be sent as HTTP referrer: username, password and ref fragment.
-  // For invalid URLs the original URL will be returned.
+  // For invalid URLs or URLs that no valid referrers, an empty URL will be
+  // returned.
   GURL GetAsReferrer() const;
 
   // Returns true if the scheme for the current URL is a known "standard"
   // scheme. Standard schemes have an authority and a path section. This
   // includes file: and filesystem:, which some callers may want to filter out
   // explicitly by calling SchemeIsFile[System].
   bool IsStandard() const;
 
   // Returns true if the given parameter (should be lower-case ASCII to match
   // the canonicalized scheme) is the scheme for this URL. This call is more
@@ skipping 191 matching lines @@
   // Used for nested schemes [currently only filesystem:].
   scoped_ptr<GURL> inner_url_;
 
   // TODO bug 684583: Add encoding for query params.
 };
 
 // Stream operator so GURL can be used in assertion statements.
 URL_EXPORT std::ostream& operator<<(std::ostream& out, const GURL& url);
 
 #endif  // URL_GURL_H_