Keep track of which attachments are referenced by which sync entries.

sync/api/attachments/fake_attachment_service.h

Index: sync/api/attachments/fake_attachment_service.h
diff --git a/sync/api/attachments/fake_attachment_service.h b/sync/api/attachments/fake_attachment_service.h
index eb97c52e1e353b3ff47871f357e678c24e3bb878..5bc443ac71daef8a220e97bd9c1f6c3f0ccbb05b 100644
--- a/sync/api/attachments/fake_attachment_service.h
+++ b/sync/api/attachments/fake_attachment_service.h
@@ -29,7 +29,8 @@ class SYNC_EXPORT FakeAttachmentService : public AttachmentService,
       OVERRIDE;
   virtual void DropAttachments(const AttachmentIdList& attachment_ids,
                                const DropCallback& callback) OVERRIDE;
-  virtual void OnSyncDataAdd(const SyncData& sync_data) OVERRIDE;
+  virtual void StoreAttachments(const AttachmentList& attachments,
+                                const StoreCallback& callback) OVERRIDE;
   virtual void OnSyncDataDelete(const SyncData& sync_data) OVERRIDE;
   virtual void OnSyncDataUpdate(const AttachmentIdList& old_attachment_ids,
                                 const SyncData& updated_sync_data) OVERRIDE;
@@ -40,6 +41,8 @@ class SYNC_EXPORT FakeAttachmentService : public AttachmentService,
                 scoped_ptr<AttachmentMap> attachments);
   void DropDone(const DropCallback& callback,
                 const AttachmentStore::Result& result);
+  void WriteDone(const StoreCallback& callback,
+                 const AttachmentStore::Result& result);
 
   const scoped_ptr<AttachmentStore> attachment_store_;
   // Must be last data member.