Move Renderer::getMajorShaderModel to RendererD3D. BUG=angle:658 Change-Id: Ibf67a96ec9c0e8d6adc4f9c839da1e06058dc32f Reviewed-on: https://chromium-review.googlesource.com/239904 Reviewed-by: Jamie Madill <jmadill@chromium.org> Tested-by: Geoff Lang <geofflang@chromium.org>