[Offline Pages] Renaming metadata store test file.

components/offline_pages/core/offline_page_metadata_store_unittest.cc

 // Copyright 2015 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 "components/offline_pages/core/offline_page_metadata_store.h"
 
 #include <stdint.h>
 
 #include <memory>
 
@@ skipping 957 matching lines @@
   std::unique_ptr<OfflinePageMetadataStore> store(BuildStore());
 
   store->Reset(base::Bind(&OfflinePageMetadataStoreTest::ResetCallback,
                           base::Unretained(this)));
   PumpLoop();
   EXPECT_EQ(STATUS_TRUE, last_status_);
 }
 
 }  // namespace
 }  // namespace offline_pages