Introduce a couple of abstract bases for WebDataService.

chrome/browser/webdata/web_data_service.cc

Index: chrome/browser/webdata/web_data_service.cc
diff --git a/chrome/browser/webdata/web_data_service.cc b/chrome/browser/webdata/web_data_service.cc
index 84514fe7a6b367dcb7f81f9fdbc23cbf38ebfbb0..ee8733fa13580311443872a8b85ac012676e1908 100644
--- a/chrome/browser/webdata/web_data_service.cc
+++ b/chrome/browser/webdata/web_data_service.cc
@@ -61,7 +61,7 @@ void NotifyOfMultipleAutofillChangesTask(
 
   content::NotificationService::current()->Notify(
       chrome::NOTIFICATION_AUTOFILL_MULTIPLE_CHANGED,
-      content::Source<WebDataService>(web_data_service.get()),
+      content::Source<WebDataServiceBase>(web_data_service.get()),
       content::NotificationService::NoDetails());
 }
 
@@ -81,8 +81,7 @@ WDKeywordsResult::WDKeywordsResult()
 WDKeywordsResult::~WDKeywordsResult() {}
 
 WebDataService::WebDataService()
-    : RefcountedProfileKeyedService(BrowserThread::UI),
-      is_running_(false),
+    : is_running_(false),
       db_(NULL),
       autocomplete_syncable_service_(NULL),
       autofill_profile_syncable_service_(NULL),
@@ -140,6 +139,10 @@ void WebDataService::CancelRequest(Handle h) {
   i->second->Cancel();
 }
 
+content::NotificationSource WebDataService::GetNotificationSource() {
+  return content::Source<WebDataService>(this);
+}
+
 bool WebDataService::IsDatabaseLoaded() {
   return db_ != NULL;
 }