Abstract content::BrowserThread usage out of AutofillWebDataBackendImpl.

components/autofill/core/browser/webdata/autofill_webdata_backend_impl.h

Index: components/autofill/core/browser/webdata/autofill_webdata_backend_impl.h
diff --git a/components/autofill/core/browser/webdata/autofill_webdata_backend_impl.h b/components/autofill/core/browser/webdata/autofill_webdata_backend_impl.h
index 8015dd4212c88878c87ad3a3432bcc96c908d1aa..9dc760e4124419988cc5f4843fc8aaa30c23e1bc 100644
--- a/components/autofill/core/browser/webdata/autofill_webdata_backend_impl.h
+++ b/components/autofill/core/browser/webdata/autofill_webdata_backend_impl.h
@@ -6,7 +6,9 @@
 #define COMPONENTS_AUTOFILL_CORE_BROWSER_WEBDATA_AUTOFILL_WEBDATA_BACKEND_IMPL_H_
 
 #include "base/memory/ref_counted.h"
+#include "base/memory/ref_counted_delete_on_message_loop.h"
 #include "base/memory/scoped_ptr.h"
+#include "base/message_loop/message_loop_proxy.h"

[Ilya Sherman, 2013/10/02 23:27:01]

nit: Seems like this could just be forward-declared.

[blundell, 2013/10/03 05:23:34]

Done.

 #include "base/observer_list.h"
 #include "base/supports_user_data.h"
 #include "components/autofill/core/browser/webdata/autofill_webdata.h"
@@ -16,7 +18,6 @@
 #include "components/webdata/common/web_data_service_base.h"
 #include "components/webdata/common/web_data_service_consumer.h"
 #include "components/webdata/common/web_database.h"
-#include "content/public/browser/browser_thread.h"
 
 class WebDataServiceBackend;
 
@@ -32,17 +33,21 @@ class CreditCard;
 // in it should only be called from that thread. Most functions here are just
 // the implementations of the corresponding functions in the Autofill
 // WebDataService.
+// This class is destroyed on the DB thread.
 class AutofillWebDataBackendImpl
-    : public base::RefCountedThreadSafe<AutofillWebDataBackendImpl,
-          content::BrowserThread::DeleteOnDBThread>,
+    : public base::RefCountedDeleteOnMessageLoop<AutofillWebDataBackendImpl>,
       public AutofillWebDataBackend {
  public:
   // |web_database_backend| is used to access the WebDatabase directly for
-  // Sync-related operations. |on_changed_callback| is a closure which can be
-  // used to notify the UI thread of changes initiated by Sync (this callback
-  // may be called multiple times).
+  // Sync-related operations. |ui_thread| and |db_thread| are the threads that
+  // this class uses as its UI and DB threads respectively.
+  // |on_changed_callback| is a closure which can be used to notify the UI
+  // thread of changes initiated by Sync (this callback may be called multiple
+  // times).
   AutofillWebDataBackendImpl(
       scoped_refptr<WebDataServiceBackend> web_database_backend,
+      const scoped_refptr<base::MessageLoopProxy>& ui_thread,
+      const scoped_refptr<base::MessageLoopProxy>& db_thread,

[Ilya Sherman, 2013/10/02 23:27:01]

Hmm, should scoped_refptrs really be passed by const-reference?  The one above
is just passed by value, which seems potentially more appropriate.

[blundell, 2013/10/03 05:23:34]

Looking through the codebase, both get used. I'll change these for local
consistency and will consider posting the question on chromium-dev@.

On 2013/10/02 23:27:01, Ilya Sherman wrote:

       const base::Closure& on_changed_callback);
 
   // AutofillWebDataBackend implementation.
@@ -137,13 +142,8 @@ class AutofillWebDataBackendImpl
   virtual ~AutofillWebDataBackendImpl();
 
  private:
-  friend struct content::BrowserThread::DeleteOnThread<
-      content::BrowserThread::DB>;
+  friend class base::RefCountedDeleteOnMessageLoop<AutofillWebDataBackendImpl>;
   friend class base::DeleteHelper<AutofillWebDataBackendImpl>;
-  // We have to friend RCTS<> so WIN shared-lib build is happy
-  // (http://crbug/112250).
-  friend class base::RefCountedThreadSafe<AutofillWebDataBackendImpl,
-      content::BrowserThread::DeleteOnDBThread>;
 
   // This makes the destructor public, and thus allows us to aggregate
   // SupportsUserData. It is private by default to prevent incorrect
@@ -157,6 +157,12 @@ class AutofillWebDataBackendImpl
     DISALLOW_COPY_AND_ASSIGN(SupportsUserDataAggregatable);
   };
 
+  // The MessageLoopProxy that this class uses as its UI thread.
+  scoped_refptr<base::MessageLoopProxy> ui_thread_;
+
+  // The MessageLoopProxy that this class uses as its DB thread.
+  scoped_refptr<base::MessageLoopProxy> db_thread_;
+
   // Storage for user data to be accessed only on the DB thread. May
   // be used e.g. for SyncableService subclasses that need to be owned
   // by this object. Is created on first call to |GetDBUserData()|.