Roll src/third_party/shaderc/src 9ad78aa7dba2..a4f9acedf3c0 (1 commits)

https://chromium.googlesource.com/external/github.com/google/shaderc/+log/9ad78aa7dba2..a4f9acedf3c0

git log 9ad78aa7dba2..a4f9acedf3c0 --date=short --first-parent --format='%ad %ae %s'
2020-01-23 rharrison@google.com Big cleanup to normalize API behaviour (#967)

Created with:
  gclient setdep -r src/third_party/shaderc/src@a4f9acedf3c0

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/+/master/autoroll/README.md

Bug: None
Tbr: radial-bots+chrome-roll@google.com
Change-Id: I63e1ccddd1831d15caec16c72b2b74b6a666e984
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2017653Reviewed-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@{#734616}

DEPS

@@ -308,7 +308,7 @@ 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': '9ad78aa7dba268ef8b808d23b135ea636fd893b1',
+  'shaderc_revision': 'a4f9acedf3c042537db8b28065728df484ca5663',
   # Three lines of non-changing comments so that
   # the commit queue can handle CLs rolling feed
   # and whatever else without interference from each other.