Refactor FakeAttachmentStore

sync/api/attachments/attachment_store.cc

Index: sync/api/attachments/attachment_store.cc
diff --git a/sync/api/attachments/attachment_store.cc b/sync/api/attachments/attachment_store.cc
index e22b040e3dec3e691b35179b5dc3bae05bb18927..6bf4aad53101689d0dc63253ecbdbf4abf7118b1 100644
--- a/sync/api/attachments/attachment_store.cc
+++ b/sync/api/attachments/attachment_store.cc
@@ -4,9 +4,24 @@
 
 #include "sync/api/attachments/attachment_store.h"
 
+#include "base/thread_task_runner_handle.h"
+#include "sync/internal_api/public/attachments/attachment_store_proxy.h"
+#include "sync/internal_api/public/attachments/in_memory_attachment_store.h"
+
 namespace syncer {
 
+AttachmentStoreBase::AttachmentStoreBase() {}
+AttachmentStoreBase::~AttachmentStoreBase() {}
+
 AttachmentStore::AttachmentStore() {}
 AttachmentStore::~AttachmentStore() {}
 
+scoped_refptr<AttachmentStore> AttachmentStore::CreateInMemoryStore() {
+  // Both frontend and backend of attachment store will live on current thread.
+  scoped_ptr<AttachmentStoreBase> backend(
+      new InMemoryAttachmentStore(base::ThreadTaskRunnerHandle::Get()));
+  return scoped_refptr<AttachmentStore>(new AttachmentStoreProxy(
+      backend.Pass(), base::ThreadTaskRunnerHandle::Get()));
+}
+
 }  // namespace syncer