Introduce url::Origin to represent Web Origin.

url/origin.cc

+// Copyright 2014 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.
+
+#include "url/origin.h"
+
+#include "base/strings/string_util.h"
+
+namespace url {
+
+Origin::Origin() : string_("null") {}
+
+Origin::Origin(const std::string& origin) : string_(origin) {
+  DCHECK(origin == "null" || MatchPattern(origin, "?*://?*"));
+  DCHECK_GT(origin.size(), 0u);
+  DCHECK_NE(origin[origin.size() - 1], '/');
+}
+
+}  // namespace url