Add ExtensionsTestBrowserContext class for test.

extensions/common/extensions_test_browser_context.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_COMMON_EXTENSIONS_TEST_BROWSER_CONTEXT_H_
+#define EXTENSIONS_COMMON_EXTENSIONS_TEST_BROWSER_CONTEXT_H_
+
+#include "content/public/test/test_browser_context.h"
+
+namespace extensions {
+
+// An implementation of BrowserContext used for extension testing. It will set
+// necessary extension state like the ExtensionsBrowserClient and any keyed
+// services, and cleans up after itself on destruction.
+class ExtensionsTestBrowserContext : public content::TestBrowserContext {
+ public:
+  ExtensionsTestBrowserContext();
+  virtual ~ExtensionsTestBrowserContext();
+
+ private:
+  DISALLOW_COPY_AND_ASSIGN(ExtensionsTestBrowserContext);
+};
+
+}  // namespace extensions
+
+#endif  // EXTENSIONS_COMMON_EXTENSIONS_TEST_BROWSER_CONTEXT_H_