Reserve an isolated world ID for Chrome Translate

chrome/renderer/isolated_world_ids.h

+// Copyright (c) 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 CHROME_RENDERER_ISOLATED_WORLD_IDS_H_
+#define CHROME_RENDERER_ISOLATED_WORLD_IDS_H_
+
+namespace chrome {
+
+enum IsolatedWorldIDs {
+  // Chrome can not use ID 0 for isolated world.
+  ISOLATED_WORLD_ID_GLOBAL = 0,
+  // Isolated world ID for Chrome Translate.
+  ISOLATED_WORLD_ID_TRANSLATE,
+
+  // UserScriptSlave::GetIsolatedWorldIdForExtension assigns numbers which are
+  // equal to, or larger than this number.
+  ISOLATED_WORLD_ID_EXTENSIONS
+};
+
+}  // namespace chrome
+
+#endif  // CHROME_RENDERER_ISOLATED_WORLD_IDS_H_