void ImageBridgeChild::ConnectAsync(ImageBridgeParent* aParent)
{
  GetMessageLoop()->PostTask(FROM_HERE, NewRunnableFunction(&ConnectImageBridge, 
                                                            this, aParent));
}
// static
void ImageBridgeChild::DispatchReleaseImageClient(ImageClient* aClient)
{
  sImageBridgeChildSingleton->GetMessageLoop()->PostTask(
    FROM_HERE,
    NewRunnableFunction(&ReleaseImageClientNow, aClient));
}