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 f86f28fd12b88c0580eb5f88245ef94eaedaf5aa..81b1dee818e53eb1dfc9495c556baeddcf4f5824 100644
--- a/chrome/browser/webdata/web_data_service_factory.cc
+++ b/chrome/browser/webdata/web_data_service_factory.cc
@@ -6,9 +6,27 @@
 
 #include "base/file_path.h"
 #include "chrome/browser/profiles/profile_dependency_manager.h"
+#include "chrome/browser/webdata/autofill_web_data_service_impl.h"
 #include "chrome/browser/webdata/web_data_service.h"
 #include "chrome/common/chrome_constants.h"
 
+// static
+scoped_ptr<AutofillWebDataService> AutofillWebDataService::ForContext(
+    content::BrowserContext* context) {
+  // For this service, the implicit/explicit distinction doesn't
+  // really matter; it's just used for a DCHECK.  So we currently
+  // cheat and always say EXPLICIT_ACCESS.
+  scoped_refptr<WebDataService> service = WebDataServiceFactory::GetForProfile(
+      static_cast<Profile*>(context), Profile::EXPLICIT_ACCESS);
+
+  if (service.get()) {
+    return scoped_ptr<AutofillWebDataService>(
+        new AutofillWebDataServiceImpl(service));
+  } else {
+    return scoped_ptr<AutofillWebDataService>(NULL);
+  }
+}
+
 WebDataServiceFactory::WebDataServiceFactory()
     : RefcountedProfileKeyedServiceFactory(
           "WebDataService",
@@ -21,6 +39,9 @@ WebDataServiceFactory::~WebDataServiceFactory() {}
 // static
 scoped_refptr<WebDataService> WebDataServiceFactory::GetForProfile(
     Profile* profile, Profile::ServiceAccessType access_type) {
+  // If |access_type| starts being used for anything other than this
+  // DCHECK, we need to start taking it as a parameter to
+  // AutofillWebDataServiceImpl::ForContext (see above).
   DCHECK(access_type != Profile::IMPLICIT_ACCESS || !profile->IsOffTheRecord());
   return static_cast<WebDataService*>(
       GetInstance()->GetServiceForProfile(profile, true).get());