Roll src/third_party/glslang/src 6e384fef6c0f..27ec91958501 (2 commits)

https://chromium.googlesource.com/external/github.com/KhronosGroup/glslang/+log/6e384fef6c0f..27ec91958501


git log 6e384fef6c0f..27ec91958501 --date=short --no-merges --format='%ad %ae %s'
2019-05-17 johnkslang@users.noreply.github.com Merge pull request #1768 from ShabbyX/enable-opt
2019-05-16 johnkslang@users.noreply.github.com Merge pull request #1767 from dneto0/update-spirv-headers


Created with:
  gclient setdep -r src/third_party/glslang/src@27ec91958501

The AutoRoll server is located here: https://autoroll.skia.org/r/glslang-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=radial-bots+chrome-roll@google.com,ynovikov@google.com

Change-Id: I25856edfeee1b584aa9a0363f4fb686e13789eb8
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1619655Reviewed-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@{#661339}

DEPS

@@ -896,7 +896,7 @@ deps = {
   },
 
   'src/third_party/glslang/src':
-    Var('chromium_git') + '/external/github.com/KhronosGroup/glslang.git' + '@' + '6e384fef6c0fcd99395502217737be87b37e2218',
+    Var('chromium_git') + '/external/github.com/KhronosGroup/glslang.git' + '@' + '27ec9195850108c8495dbc1ee2a10d09e8ea1921',
 
   'src/third_party/google_toolbox_for_mac/src': {
       'url': Var('chromium_git') + '/external/github.com/google/google-toolbox-for-mac.git' + '@' + Var('google_toolbox_for_mac_revision'),