[Sync] Refactor AttachmentStore classes. Introduce concept of referrer.

sync/internal_api/attachments/on_disk_attachment_store_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 "sync/internal_api/public/attachments/on_disk_attachment_store.h"
 
 #include "base/files/file_path.h"
 #include "base/files/file_util.h"
 #include "base/files/scoped_temp_dir.h"
 #include "base/message_loop/message_loop.h"
@@ skipping 19 matching lines @@
 }
 
 }  // namespace
 
 // Instantiation of common attachment store tests.
 class OnDiskAttachmentStoreFactory {
  public:
   OnDiskAttachmentStoreFactory() {}
   ~OnDiskAttachmentStoreFactory() {}
 
-  scoped_refptr<AttachmentStore> CreateAttachmentStore() {
+  scoped_ptr<AttachmentStore> CreateAttachmentStore() {
     EXPECT_TRUE(temp_dir_.CreateUniqueTempDir());
-    scoped_refptr<AttachmentStore> store;
+    scoped_ptr<AttachmentStore> store;
     AttachmentStore::Result result = AttachmentStore::UNSPECIFIED_ERROR;
     store = AttachmentStore::CreateOnDiskStore(
         temp_dir_.path(), base::ThreadTaskRunnerHandle::Get(),
         base::Bind(&AttachmentStoreCreated, &result));
     base::RunLoop run_loop;
     run_loop.RunUntilIdle();
     EXPECT_EQ(AttachmentStore::SUCCESS, result);
     return store;
   }
 
  private:
   base::ScopedTempDir temp_dir_;
 };
 
 INSTANTIATE_TYPED_TEST_CASE_P(OnDisk,
                               AttachmentStoreTest,
                               OnDiskAttachmentStoreFactory);
 
 // Tests specific to OnDiskAttachmentStore.
 class OnDiskAttachmentStoreSpecificTest : public testing::Test {
  public:
   base::ScopedTempDir temp_dir_;
   base::FilePath db_path_;
   base::MessageLoop message_loop_;
-  scoped_refptr<AttachmentStore> store_;
+  scoped_ptr<AttachmentStore> store_;
 
   OnDiskAttachmentStoreSpecificTest() {}
 
   void SetUp() override {
     ASSERT_TRUE(temp_dir_.CreateUniqueTempDir());
     db_path_ = temp_dir_.path().Append(FILE_PATH_LITERAL("leveldb"));
     base::CreateDirectory(db_path_);
   }
 
   void CopyResult(AttachmentStore::Result* destination_result,
@@ skipping 390 matching lines @@
   store_->ReadAllMetadata(
       base::Bind(&OnDiskAttachmentStoreSpecificTest::CopyResultMetadata,
                  base::Unretained(this), &metadata_result, &metadata_list));
   RunLoop();
   EXPECT_EQ(AttachmentStore::SUCCESS, create_result);
   EXPECT_EQ(AttachmentStore::UNSPECIFIED_ERROR, metadata_result);
   EXPECT_EQ(2U, metadata_list->size());
 }
 
 }  // namespace syncer