Create ExtensionsRendererClient.

extensions/renderer/extensions_renderer_client.h

+// 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.
+
+#ifndef EXTENSIONS_RENDERER_EXTENSIONS_RENDERER_CLIENT_H_
+#define EXTENSIONS_RENDERER_EXTENSIONS_RENDERER_CLIENT_H_
+
+namespace extensions {
+
+// Interface to allow the extensions module to make render-process-specific
+// queries of the embedder. Should be Set() once in the render process.
+//
+// NOTE: Methods that do not require knowledge of renderer concepts should be
+// added in ExtensionsClient (extensions/common/extensions_client.h) even if
+// they are only used in the renderer process.
+class ExtensionsRendererClient {
+ public:
+  virtual ~ExtensionsRendererClient() {}
+
+  // Returns true if the current render process was launched incognito.
+  virtual bool IsIncognitoProcess() const = 0;
+
+  // Returns the lowest isolated world ID available to extensions.

[Yoyo Zhou, 2014/04/14 21:39:05]

There should be a "See ..." pointer here.

+  virtual int GetLowestIsolatedWorldId() const = 0;
+
+  // Returns the single instance of |this|.
+  static ExtensionsRendererClient* Get();
+
+  // Initialize the single instance.
+  static void Set(ExtensionsRendererClient* client);
+};
+
+}  // namespace extensions
+
+#endif  // EXTENSIONS_RENDERER_EXTENSIONS_RENDERER_CLIENT_H_