cros: Restrict gaiaURL to be http and https only.

chrome/browser/resources/gaia_auth/util.js

Index: chrome/browser/resources/gaia_auth/util.js
diff --git a/chrome/browser/resources/gaia_auth/util.js b/chrome/browser/resources/gaia_auth/util.js
index 9d8ebd7237d156b6acffdc7f4b347ca3d122eafc..039465ab87cce15c02fc54323cb92939d08b9f68 100644
--- a/chrome/browser/resources/gaia_auth/util.js
+++ b/chrome/browser/resources/gaia_auth/util.js
@@ -72,3 +72,15 @@ function extractDomain(url) {
   a.href = url;
   return a.hostname;
 }
+
+/**
+ * Extract protocol from an URL.
+ * @param {string} url An URL string.
+ * @return {string} The protocol of the URL.
+ */
+function extractProtocol(url) {
+  var a = document.createElement('a');
+  a.href = url;
+  return a.protocol;
+}
+