Compile fix for gcc 4.6 (WebDataService::Handle is typedef of int).

chrome/browser/sync/profile_sync_service_autofill_unittest.cc

Index: chrome/browser/sync/profile_sync_service_autofill_unittest.cc
diff --git a/chrome/browser/sync/profile_sync_service_autofill_unittest.cc b/chrome/browser/sync/profile_sync_service_autofill_unittest.cc
index 50c7b32c81d8902c92a5b2c8a9a6da6462ca4138..f3487b7149378af93ae8ea0d42c49ca0ea335566 100644
--- a/chrome/browser/sync/profile_sync_service_autofill_unittest.cc
+++ b/chrome/browser/sync/profile_sync_service_autofill_unittest.cc
@@ -194,7 +194,7 @@ class WebDataServiceFake : public WebDataService {
     // initialization (which seems way more fragile) we can't tell which
     // component is asking at what time, and some components in these Autofill
     // tests require a WebDataService.
-    return NULL;
+    return 0;
   }
 
   virtual AutocompleteSyncableService*