Create an AutofillBackend interface

components/autofill/browser/webdata/autofill_webdata_service.cc

Index: components/autofill/browser/webdata/autofill_webdata_service.cc
diff --git a/components/autofill/browser/webdata/autofill_webdata_service.cc b/components/autofill/browser/webdata/autofill_webdata_service.cc
index 217f2651e9c105d7b24d829160564ef98e3b3521..c2a5550c6ba76949c7a3abce54882588c4e98591 100644
--- a/components/autofill/browser/webdata/autofill_webdata_service.cc
+++ b/components/autofill/browser/webdata/autofill_webdata_service.cc
@@ -15,6 +15,7 @@
 #include "components/autofill/browser/webdata/autofill_webdata_backend.h"
 #include "components/autofill/browser/webdata/autofill_webdata_service_observer.h"
 #include "components/autofill/common/form_field_data.h"
+#include "components/webdata/common/web_data_service_backend.h"
 #include "components/webdata/common/web_database_service.h"
 
 using base::Bind;
@@ -41,16 +42,27 @@ AutofillWebDataService::AutofillWebDataService(
     scoped_refptr<WebDatabaseService> wdbs,
     const ProfileErrorCallback& callback)
     : WebDataServiceBase(wdbs, callback),
-      autofill_backend_(new AutofillWebDataBackend()) {
+      weak_ptr_factory_(this),
+      autofill_backend_(NULL) {
+
+  base::Closure on_changed_callback = Bind(
+      &AutofillWebDataService::NotifyAutofillMultipleChangedOnUIThread,
+      weak_ptr_factory_.GetWeakPtr());
+
+  autofill_backend_ = new AutofillWebDataBackend(
+      wdbs_->GetBackend(),
+      on_changed_callback);
 }
 
 AutofillWebDataService::AutofillWebDataService()
     : WebDataServiceBase(NULL,
                          WebDataServiceBase::ProfileErrorCallback()),
-      autofill_backend_(new AutofillWebDataBackend()) {
+      weak_ptr_factory_(this),
+      autofill_backend_(new AutofillWebDataBackend(NULL, base::Closure())) {
 }
 
 void AutofillWebDataService::ShutdownOnUIThread() {
+  weak_ptr_factory_.InvalidateWeakPtrs();
   BrowserThread::PostTask(
     BrowserThread::DB, FROM_HERE,
     base::Bind(&AutofillWebDataService::ShutdownOnDBThread, this));
@@ -190,6 +202,13 @@ base::SupportsUserData* AutofillWebDataService::GetDBUserData() {
   return db_thread_user_data_.get();
 }
 
+void AutofillWebDataService::GetSyncableBackend(
+    const base::Callback<void(SyncableServiceBackend*)>& callback) {
+  BrowserThread::PostTask(BrowserThread::DB,
+                          FROM_HERE,
+                          base::Bind(callback, autofill_backend_));
+}
+
 void AutofillWebDataService::ShutdownOnDBThread() {
   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::DB));
   db_thread_user_data_.reset();