We're finding that D3Dcompile is being called with a null
compiler handle. This means at some point we successfully linked
a program, using a valid compiler handle, and likely we went
through some traumatic event like a GPU device lost. This unloaded
the compiler DLL and hence leads to a null deref.

It's not clear how this is happening since a device lost should
trigger a restart of the browser process in all cases with Chrome,
but this should fix the NULL deref and lead to a user-visible
program link error.

BUG=chromium:671162

Change-Id: Ibf85f19d4f099d2f00921c230ee0a52b46bfd8cf
Reviewed-on: https://chromium-review.googlesource.com/422553Reviewed-by: Jamie Madill <jmadill@chromium.org>
Commit-Queue: Jamie Madill <jmadill@chromium.org>