Update sync API to support attachments.

sync/api/attachments/fake_attachment_store.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 SYNC_API_ATTACHMENTS_FAKE_ATTACHMENT_STORE_H_
 #define SYNC_API_ATTACHMENTS_FAKE_ATTACHMENT_STORE_H_
 
 #include <map>
 
 #include "base/memory/ref_counted.h"
@@ skipping 15 matching lines @@
 
 class Attachment;
 
 // A in-memory only implementation of AttachmentStore used for testing.
 //
 // Requires that the current thread has a MessageLoop.
 class SYNC_EXPORT FakeAttachmentStore : public AttachmentStore {
  public:
   // Construct a FakeAttachmentStore whose "IO" will be performed in
   // |backend_task_runner|.
-  FakeAttachmentStore(
+  explicit FakeAttachmentStore(
       const scoped_refptr<base::SequencedTaskRunner>& backend_task_runner);
 
   virtual ~FakeAttachmentStore();
 
   // AttachmentStore implementation.
   virtual void Read(const sync_pb::AttachmentId& id,
                     const ReadCallback& callback) OVERRIDE;
   virtual void Write(const scoped_refptr<base::RefCountedMemory>& bytes,
                      const WriteCallback& callback) OVERRIDE;
   virtual void Drop(const sync_pb::AttachmentId& id,
                     const DropCallback& callback) OVERRIDE;
 
  private:
   class Backend;
 
   scoped_refptr<Backend> backend_;
   scoped_refptr<base::SequencedTaskRunner> backend_task_runner_;
 
   DISALLOW_COPY_AND_ASSIGN(FakeAttachmentStore);
 };
 
 }  // namespace syncer
 
 #endif  // SYNC_API_ATTACHMENTS_FAKE_ATTACHMENT_STORE_H_