Makes GetComponentExtensionResourceManager() thread-safe.

chrome/browser/extensions/chrome_component_extension_resource_manager_unittest.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 "base/files/file_path.h"
 #include "base/path_service.h"
 #include "chrome/common/chrome_paths.h"
 #include "extensions/browser/component_extension_resource_manager.h"
 #include "extensions/browser/extensions_browser_client.h"
 #include "extensions/common/constants.h"
 #include "extensions/common/extension.h"
 #include "extensions/common/extension_icon_set.h"
 #include "extensions/common/extension_resource.h"
 #include "extensions/common/file_util.h"
 #include "extensions/common/manifest.h"
 #include "extensions/common/manifest_handlers/icons_handler.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
 #if defined(OS_CHROMEOS)
 #include "ui/file_manager/grit/file_manager_resources.h"
 #endif
 
 namespace extensions {
 
 typedef testing::Test ChromeComponentExtensionResourceManagerTest;
 
 // Tests IsComponentExtensionResource function.
 TEST_F(ChromeComponentExtensionResourceManagerTest,
        IsComponentExtensionResource) {
-  ComponentExtensionResourceManager* resource_manager =
+  const ComponentExtensionResourceManager* resource_manager =
       ExtensionsBrowserClient::Get()->GetComponentExtensionResourceManager();
   ASSERT_TRUE(resource_manager);
 
   // Get the extension test data path.
   base::FilePath test_path;
   ASSERT_TRUE(PathService::Get(chrome::DIR_TEST_DATA, &test_path));
   test_path = test_path.AppendASCII("extensions").AppendASCII("file_manager");
 
   // Load the manifest data.
   std::string error;
@@ skipping 24 matching lines @@
 #if defined(OS_CHROMEOS)
   // The resource is a component resource.
   int resource_id = 0;
   ASSERT_TRUE(resource_manager->IsComponentExtensionResource(
       extension->path(), resource.relative_path(), &resource_id));
   ASSERT_EQ(IDR_FILE_MANAGER_ICON_16, resource_id);
 #endif
 }
 
 }  // namespace extensions