Introduce a couple of abstract bases for WebDataService.

chrome/browser/webdata/web_data_service_factory.cc

Index: chrome/browser/webdata/web_data_service_factory.cc
diff --git a/chrome/browser/webdata/web_data_service_factory.cc b/chrome/browser/webdata/web_data_service_factory.cc
index 006a0fc7a3585dd205cc3409a3a8af9882551720..5c0968d0feaf4185fb42992c6928ab69bc707830 100644
--- a/chrome/browser/webdata/web_data_service_factory.cc
+++ b/chrome/browser/webdata/web_data_service_factory.cc
@@ -9,6 +9,15 @@
 #include "chrome/browser/webdata/web_data_service.h"
 #include "chrome/common/chrome_constants.h"
 
+// static
+scoped_refptr<WebDataServiceBase> WebDataServiceBase::ForProfile(
+    Profile* profile) {
+  // TODO(joi): Does the implicit/explicit distinction really matter?
+  // It's just used for a DCHECK.
+  return WebDataServiceFactory::GetForProfile(profile,
+                                              Profile::EXPLICIT_ACCESS);
+}
+
 WebDataServiceFactory::WebDataServiceFactory()
     : RefcountedProfileKeyedServiceFactory(
           "WebDataService",