Drive QAbstractAnimaton-based animations using RAF. This has two main benefits: * The animation update rate automatically adapts to the screen refresh rate * The animation update happens in sync with the draw callback, instead of as an extra wakeup in between frames. Add QWasmAnimationDriver, which replaces QDefaultAnimationDriver for Q_OS_WASM. Add QWasmAnimationFrameMultiHandler. This class supports multiplexing multiple animation and draw callbacks to a single native requestAnimation call. It also orders the callbacks such that animation callbacks are called before draw callbacks. Make QWindow::requestUpdate() use the new multi-handler (via QWasmCompositor, as before) Fixes: QTBUG-133695 Change-Id: I0a3fda562a7ba2e8d659d707335d1ce116f71bd9 Reviewed-by: Morten Johan Sørvig <morten.sorvig@qt.io> Reviewed-by: Even Oscar Andersen <even.oscar.andersen@qt.io>