Create an AutofillBackend interface

components/webdata/common/web_data_service_backend.cc

Index: components/webdata/common/web_data_service_backend.cc
diff --git a/components/webdata/common/web_data_service_backend.cc b/components/webdata/common/web_data_service_backend.cc
index 3b945b0b540f721304917c9d135b52a16689f890..300b182bc84e856f02c857cce1428737585640cb 100644
--- a/components/webdata/common/web_data_service_backend.cc
+++ b/components/webdata/common/web_data_service_backend.cc
@@ -73,23 +73,40 @@ void WebDataServiceBackend::ShutdownDatabase(bool should_reinit) {
 void WebDataServiceBackend::DBWriteTaskWrapper(
     const WebDatabaseService::WriteTask& task,
     scoped_ptr<WebDataRequest> request) {
+  if (request->IsCancelled())
+    return;
+
+  ExecuteWriteTask(task);
+  request_manager_->RequestCompleted(request.Pass());
+}
+
+void WebDataServiceBackend::ExecuteWriteTask(
+    const WebDatabaseService::WriteTask& task) {
   LoadDatabaseIfNecessary();
-  if (db_ && init_status_ == sql::INIT_OK && !request->IsCancelled()) {
+  if (db_ && init_status_ == sql::INIT_OK) {
     WebDatabase::State state = task.Run(db_.get());
     if (state == WebDatabase::COMMIT_NEEDED)
       Commit();
   }
-  request_manager_->RequestCompleted(request.Pass());
 }
 
 void WebDataServiceBackend::DBReadTaskWrapper(
     const WebDatabaseService::ReadTask& task,
     scoped_ptr<WebDataRequest> request) {
+  if (request->IsCancelled())
+    return;
+
+  request->SetResult(ExecuteReadTask(task).Pass());
+  request_manager_->RequestCompleted(request.Pass());
+}
+
+scoped_ptr<WDTypedResult> WebDataServiceBackend::ExecuteReadTask(
+    const WebDatabaseService::ReadTask& task) {
   LoadDatabaseIfNecessary();
-  if (db_ && init_status_ == sql::INIT_OK && !request->IsCancelled()) {
-    request->SetResult(task.Run(db_.get()).Pass());
+  if (db_ && init_status_ == sql::INIT_OK) {
+    return task.Run(db_.get());
   }
-  request_manager_->RequestCompleted(request.Pass());
+  return scoped_ptr<WDTypedResult>(NULL);
 }
 
 WebDataServiceBackend::~WebDataServiceBackend() {