There are a couple of runnables (in Console and in BindingUtils) that use WorkerHolder just to keep the worker alive. With this patch I want to unify these runnables implementing a common base class and use ModifyBusyCount instead using WorkerHolder. This is a good first step to make WorkerHolder a thread-only class so that we can add assertions in the CTOR and in the DTOR.

Comment on attachment 8765362 [details] [diff] [review] holder.patch Review of attachment 8765362 [details] [diff] [review]: ----------------------------------------------------------------- ::: dom/indexedDB/ActorsChild.cpp @@ +927,5 @@ > + if (NS_WARN_IF(!mWorkerPrivate->ModifyBusyCountFromWorker(true))) { > + return false; > + } > + > + if (NS_WARN_IF(NS_FAILED(NS_DispatchToMainThread(this)))) { here too ::: dom/workers/WorkerRunnable.cpp @@ +721,5 @@ > + RunBackOnWorkerThread(); > + return false; > + } > + > + if (NS_WARN_IF(NS_FAILED(NS_DispatchToMainThread(this)))) { NS_DispatchToMainThread can't fail until after xpcom-shutdown-threads, at which point the worker has to be gone. So you can MOZ_ALWAYS_SUCCEEDS this. ::: dom/workers/WorkerRunnable.h @@ +410,5 @@ > > +// This runnable is an helper class for dispatching something from a worker > +// thread to the main-thread and back to the worker-thread. During this > +// operation, this class will keep the worker alive. > +class WorkerToMainThreadRunnable : public Runnable I have to admit that I don't care for this name, but I can't think of anything much better. WorkerProxyToMainThreadRunnable? WorkerPingPongToMainThreadRunnable? :P I think the name needs to indicate that it comes back ...

Pushed by amarchesini@mozilla.com: https://hg.mozilla.org/integration/mozilla-inbound/rev/cc14db264521 Improve WorkerHolder use in Runnables, r=khuey