In https://bugs.webkit.org/show_bug.cgi?id=43589 we are changing GraphicsLayer::setContentsToWebGL to GraphicsLayer::setContentsToPlatformLayer. We can use this same interface in place of GraphicsLayer::setContentsToMediaLayer. The only difference between the two is that for media layer we don't call setNeedsDisplay when setting the layer. We can probably make doing do safe for media layer.