Bug 262743

Currently, a NativePromise takes a SerialFunctionDispatcher. There are cases where we want when the NativePromise settle to resolve the DOMPromise on a particular event loop. Right now, this requires to call `queueTaskKeepingObjectAlive` within the resolve/reject callback like so https://searchfox.org/wubkat/rev/ba90462eb61f1fb629a567d01716a8e20c261060/Source/WebCore/Modules/webaudio/BaseAudioContext.cpp#303-318 ``` p->whenSettled(RunLoop::main(), [this, activity = makePendingActivity(*this), successCallback = WTFMove(successCallback), errorCallback = WTFMove(errorCallback), promise = WTFMove(promise)] (DecodingTaskPromise::Result&& result) mutable { queueTaskKeepingObjectAlive(*this, TaskSource::InternalAsyncTask, [successCallback = WTFMove(successCallback), errorCallback = WTFMove(errorCallback), promise = WTFMove(promise), result = WTFMove(result)]() mutable { if (!result) { if (promise) promise.value()->reject(Exception { result.error(), "Decoding failed"_s }); if (errorCallback) errorCallback->handleEvent(nullptr); return; } auto audioBuffer = WTFMove(result.value()); if (promise) promise.value()->resolve<IDLInterface<AudioBuffer>>(audioBuffer.get()); if (successCallback) successCallback->handleEvent(audioBuffer.ptr()); }); }); ``` ` Ideally, you would be able to get a ref-counted SerialFunctionDispatcher from the ActiveDOMOBject where the dispatch method would perform the same as `queueTaskKeepingObjectAlive` (wrap the dispatched runnable into a EventLoopTask and dispatch it.