Create an AutofillBackend interface

components/autofill/browser/webdata/autofill_webdata_service.h

Index: components/autofill/browser/webdata/autofill_webdata_service.h
diff --git a/components/autofill/browser/webdata/autofill_webdata_service.h b/components/autofill/browser/webdata/autofill_webdata_service.h
index 87b967ca94bb2283270198968fe60b21399cfbf4..7df052fad11debf6c44cb0f7d299d0f47192cb8d 100644
--- a/components/autofill/browser/webdata/autofill_webdata_service.h
+++ b/components/autofill/browser/webdata/autofill_webdata_service.h
@@ -8,6 +8,7 @@
 #include <vector>
 
 #include "base/memory/ref_counted.h"
+#include "base/memory/weak_ptr.h"
 #include "base/observer_list.h"
 #include "base/supports_user_data.h"
 #include "components/autofill/browser/webdata/autofill_webdata.h"
@@ -31,6 +32,7 @@ class AutofillWebDataBackend;
 class AutofillWebDataServiceObserverOnDBThread;
 class AutofillWebDataServiceObserverOnUIThread;
 class CreditCard;
+class SyncableServiceBackend;
 
 // API for Autofill web data.
 class AutofillWebDataService : public AutofillWebData,
@@ -96,11 +98,17 @@ class AutofillWebDataService : public AutofillWebData,
   // |ShutdownOnUIThread()| is called.
   base::SupportsUserData* GetDBUserData();
 
+  void GetSyncableBackend(

[Jói, 2013/05/07 19:39:41]

Needs documentation.

[Cait (Slow), 2013/05/07 20:14:56]

Done.

+      const base::Callback<void(SyncableServiceBackend*)>& callback);
  protected:
   virtual ~AutofillWebDataService();
 
   virtual void ShutdownOnDBThread();
 
+  // This factory is used on the UIThread. All vended weak pointers are
+  // invalidated in ShutdownOnUIThread().
+  base::WeakPtrFactory<AutofillWebDataService> weak_ptr_factory_;
+
  private:
   // This makes the destructor public, and thus allows us to aggregate
   // SupportsUserData. It is private by default to prevent incorrect