Roll shaderc from ffd805115ed6 to 21b36f736809 (1 revision)

https://chromium.googlesource.com/external/github.com/google/shaderc/+log/ffd805115ed6..21b36f736809

2020-08-17 rharrison@google.com Roll 4 dependencies (#1131)

If this roll has caused a breakage, revert this CL and stop the roller
using the controls here:
https://autoroll.skia.org/r/shaderc-chromium-autoroll
Please CC radial-bots+chrome-roll@google.com on the revert to ensure that a human
is aware of the problem.

To report a problem with the AutoRoller itself, please file a bug:
https://bugs.chromium.org/p/skia/issues/entry?template=Autoroller+Bug

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

Tbr: radial-bots+chrome-roll@google.com
Change-Id: Ied6c561def4ebc0c16c279da171809877eaa5b57
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2360298Reviewed-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@{#798817}

DEPS

@@ -314,7 +314,7 @@ 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.
-  'shaderc_revision': 'ffd805115ed6672ff98ce27d2034ffe1646fd834',
+  'shaderc_revision': '21b36f7368092216ecfaa017e95c383c2ed9db70',
   # Three lines of non-changing comments so that
   # the commit queue can handle CLs rolling feed
   # and whatever else without interference from each other.