Move referrer stripping into GURL::GetAsReferrer().

url/gurl.h

Index: url/gurl.h
diff --git a/url/gurl.h b/url/gurl.h
index dc88fec25c0d7468e53602fc4ad5e3d2a4b08f2d..28897d16703e514b3166878ef784d16cdfaf43ae 100644
--- a/url/gurl.h
+++ b/url/gurl.h
@@ -195,6 +195,11 @@ class URL_EXPORT GURL {
   // 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.
+  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