D3D11: Consolidate SRV and Sampler application. This adds an internal and external version of the setShaderResource method. The external version sets the state as dirty. BUG=angleproject:2052 Change-Id: I6d2d47490c0af89ff5592d4e9c53eb69f8a3264d Reviewed-on: https://chromium-review.googlesource.com/659397 Reviewed-by: Geoff Lang <geofflang@chromium.org> Commit-Queue: Jamie Madill <jmadill@chromium.org>