Don't do Negotiate with GSSAPI if default credentials are not allowed.

net/http/url_security_manager.h

Index: net/http/url_security_manager.h
diff --git a/net/http/url_security_manager.h b/net/http/url_security_manager.h
index 5f68e3ade84dcbe9b63f68711d3cd33156d63cea..cd80a7db349576e048d1ecd151a1a0ba4043786e 100644
--- a/net/http/url_security_manager.h
+++ b/net/http/url_security_manager.h
@@ -47,6 +47,22 @@ class URLSecurityManagerWhitelist : public URLSecurityManager {
   DISALLOW_COPY_AND_ASSIGN(URLSecurityManagerWhitelist);
 };
 
+#if defined(UNIT_TEST)
+// An URLSecurityManager which always allows default credentials.
+class URLSecurityManagerAllow : public URLSecurityManager {
+ public:
+  URLSecurityManagerAllow() {}
+  virtual ~URLSecurityManagerAllow() {}
+
+  virtual bool CanUseDefaultCredentials(const GURL& auth_origin) {
+    return true;
+  }
+
+ private:
+  DISALLOW_COPY_AND_ASSIGN(URLSecurityManagerAllow);
+};
+#endif  // defined(UNIT_TEST)
+
 }  // namespace net
 
 #endif  // NET_HTTP_URL_SECURITY_MANAGER_H_