Attempt skipping D3D11 shader optimization if compilation fails.

BUG=angle:648,chromium:371868

Change-Id: I1de854aad6e002bd1349f08eb8d6b597c535c90b
Reviewed-on: https://chromium-review.googlesource.com/199733
Tested-by: Nicolas Capens <nicolascapens@chromium.org>
Reviewed-by: Shannon Woods <shannonwoods@chromium.org>
1 file changed