Replace AttachmentStore's StoreAttachments with UploadAttachments.

components/sync_driver/generic_change_processor.h

Index: components/sync_driver/generic_change_processor.h
diff --git a/components/sync_driver/generic_change_processor.h b/components/sync_driver/generic_change_processor.h
index 19416004455e55c8c1e43345ff1aba1a3b367994..a3139d8161a849c81425edc8309059800823e263 100644
--- a/components/sync_driver/generic_change_processor.h
+++ b/components/sync_driver/generic_change_processor.h
@@ -13,6 +13,7 @@
 #include "components/sync_driver/change_processor.h"
 #include "components/sync_driver/data_type_controller.h"
 #include "components/sync_driver/data_type_error_handler.h"
+#include "sync/api/attachments/attachment_store.h"
 #include "sync/api/sync_change_processor.h"
 #include "sync/api/sync_merge_result.h"
 #include "sync/internal_api/public/attachments/attachment_service.h"
@@ -126,6 +127,18 @@ class GenericChangeProcessor : public ChangeProcessor,
                                        syncer::WriteNode* sync_node,
                                        syncer::AttachmentList* new_attachments);
 
+  // Store |attachments| locally then upload them to the sync server.
+  //
+  // Store and uploading are asynchronous operations.  |WriteAttachmentsDone|
+  // will be invoked once the attachments have been stored on the local device.
+  void StoreAndUploadAttachments(const syncer::AttachmentList& attachments);
+
+  // Invoked once attachments have been stored locally.
+  //
+  // See also AttachmentStore::WriteCallback.
+  void WriteAttachmentsDone(const syncer::AttachmentList& attachments,
+                            const syncer::AttachmentStore::Result& result);
+
   // The SyncableService this change processor will forward changes on to.
   const base::WeakPtr<syncer::SyncableService> local_service_;
 
@@ -155,6 +168,8 @@ class GenericChangeProcessor : public ChangeProcessor,
       attachment_service_weak_ptr_factory_;
   syncer::AttachmentServiceProxy attachment_service_proxy_;
 
+  base::WeakPtrFactory<GenericChangeProcessor> weak_ptr_factory_;
+
   DISALLOW_COPY_AND_ASSIGN(GenericChangeProcessor);
 };