Using "no_chromium_code" is a bit less strict, but ANGLE should be
able to handle slightly stricter warnings.

Re-land with fix for Clang build.

BUG=angleproject:1449

Change-Id: I8988287d630a6258f2f9ee90e7bfef5f2d5799cd
Reviewed-on: https://chromium-review.googlesource.com/361331Reviewed-by: Jamie Madill <jmadill@chromium.org>
Commit-Queue: Jamie Madill <jmadill@chromium.org>