Reland: Refactor ExtensionManifestTest to allow usage in src/extensions

chrome/common/extensions/manifest_tests/chrome_manifest_test.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 CHROME_COMMON_EXTENSIONS_MANIFEST_TESTS_CHROME_MANIFEST_TEST_H_
+#define CHROME_COMMON_EXTENSIONS_MANIFEST_TESTS_CHROME_MANIFEST_TEST_H_
+
+#include "base/macros.h"
+#include "chrome/common/extensions/features/feature_channel.h"
+#include "extensions/common/manifest_test.h"
+
+// Base class for unit tests that load manifest data from Chrome TEST_DATA_DIR.
+// TODO(jamescook): Move this class and all subclasses into the extensions
+// namespace.
+class ChromeManifestTest : public extensions::ManifestTest {
+ public:
+  ChromeManifestTest();
+  virtual ~ChromeManifestTest();
+
+  // ManifestTest overrides:
+  virtual base::FilePath GetTestDataDir() OVERRIDE;
+
+ private:
+  // Force the manifest tests to run as though they are on trunk, since several
+  // tests rely on manifest features being available that aren't on
+  // stable/beta.
+  //
+  // These objects nest, so if a test wants to explicitly test the behaviour
+  // on stable or beta, declare it inside that test.
+  extensions::ScopedCurrentChannel current_channel_;
+
+  DISALLOW_COPY_AND_ASSIGN(ChromeManifestTest);
+};
+
+#endif  // CHROME_COMMON_EXTENSIONS_MANIFEST_TESTS_CHROME_MANIFEST_TEST_H_