Roll src/third_party/SPIRV-Tools/src 6af3c5cbe4c7..67b2e1555ab6 (2 commits)

https://chromium.googlesource.com/external/github.com/KhronosGroup/SPIRV-Tools.git/+log/6af3c5cbe4c7..67b2e1555ab6


git log 6af3c5cbe4c7..67b2e1555ab6 --date=short --no-merges --format='%ad %ae %s'
2018-12-03 dj2@everburning.com Fixup BUILD.gn from addtion of upgrade_memory_model (#2152)
2018-11-30 33432579+alan-baker@users.noreply.github.com Update memory model (#1904)


Created with:
  gclient setdep -r src/third_party/SPIRV-Tools/src@67b2e1555ab6

The AutoRoll server is located here: https://autoroll.skia.org/r/spirv-tools-chromium-autoroll

Documentation for the AutoRoller is here:
https://skia.googlesource.com/buildbot/+/master/autoroll/README.md

If the roll is causing failures, please contact the current sheriff, who should
be CC'd on the roll, and stop the roller if necessary.


TBR=dsinclair@chromium.org

Change-Id: I7498d4e83f0dc6c1e168c859286ad5eaafe6c37b
Reviewed-on: https://chromium-review.googlesource.com/c/1358711Reviewed-by: chromium-autoroll <chromium-autoroll@skia-public.iam.gserviceaccount.com>
Commit-Queue: chromium-autoroll <chromium-autoroll@skia-public.iam.gserviceaccount.com>
Cr-Commit-Position: refs/heads/master@{#613098}

DEPS

@@ -220,7 +220,7 @@ vars = {
   # Three lines of non-changing comments so that
   # the commit queue can handle CLs rolling feed
   # and whatever else without interference from each other.
-  'spv_tools_revision': '6af3c5cbe4c7204e9973ed256ffb28f033864ceb',
+  'spv_tools_revision': '67b2e1555ab6977722ce2c822f1440d08af5c836',
   # Three lines of non-changing comments so that
   # the commit queue can handle CLs rolling feed
   # and whatever else without interference from each other.