D3D11: Move Constant Buffer state to StateManager11. Also moves the logic of the constant buffer sync to StateManager11. Removes a few of the remaining virtual methods in RendererD3D. BUG=angleproject:1390 BUG=angleproject:2052 Change-Id: Ia6c1c3949fff84323331510d80bbfb6e1665d294 Reviewed-on: https://chromium-review.googlesource.com/659226 Commit-Queue: Jamie Madill <jmadill@chromium.org> Reviewed-by: Geoff Lang <geofflang@chromium.org>