Create an AutofillBackend interface

components/webdata/common/web_data_service_backend.h

Index: components/webdata/common/web_data_service_backend.h
diff --git a/components/webdata/common/web_data_service_backend.h b/components/webdata/common/web_data_service_backend.h
index 0e1d8f247e7024761e519ddd4eabdb5f1bd1f299..dbde1664eea039367a13e84447e9a7e5fcbf0c49 100644
--- a/components/webdata/common/web_data_service_backend.h
+++ b/components/webdata/common/web_data_service_backend.h
@@ -29,6 +29,8 @@ class Location;
 // WebDatabaseService. It is refcounted to allow asynchronous destruction on the
 // DB thread.
 
+// TODO(caitkp): Rename this class to WebDatabaseBackend.
+
 class WebDataServiceBackend
     : public base::RefCountedThreadSafe<
           WebDataServiceBackend,
@@ -62,7 +64,10 @@ class WebDataServiceBackend
   // possible to re-initialize the DB after the shutdown.
   void ShutdownDatabase(bool should_reinit);
 
-  // Task wrappers to run database tasks.
+  // Task wrappers to update requests and and notify |request_manager_|. These
+  // are used in cases where the request is being made from the UI thread and an
+  // asyncronous callback is required to notify the client of |request|'s
+  // completion.
   void DBWriteTaskWrapper(
       const WebDatabaseService::WriteTask& task,
       scoped_ptr<WebDataRequest> request);
@@ -70,6 +75,11 @@ class WebDataServiceBackend
       const WebDatabaseService::ReadTask& task,
       scoped_ptr<WebDataRequest> request);
 
+  // Task runners to run database tasks

[Ilya Sherman, 2013/05/10 00:08:00]

nit: Please end the sentence with a period.

+  void ExecuteWriteTask(const WebDatabaseService::WriteTask& task);
+  scoped_ptr<WDTypedResult> ExecuteReadTask(
+      const WebDatabaseService::ReadTask& task);
+
   const scoped_refptr<WebDataRequestManager>& request_manager() {
     return request_manager_;
   }