Roll src/third_party/shaderc/src db3c93975a8f..dadf12a4bd9c (1 commits)

https://chromium.googlesource.com/external/github.com/google/shaderc/+log/db3c93975a8f..dadf12a4bd9c

git log db3c93975a8f..dadf12a4bd9c --date=short --first-parent --format='%ad %ae %s'
2019-12-04 rharrison@google.com Remove unused variable from C++ API (#926)

Created with:
  gclient setdep -r src/third_party/shaderc/src@dadf12a4bd9c

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: I3fca8800f8c28c00779aa29e269772c334952d8f
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1951661Reviewed-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@{#721721}

DEPS

@@ -299,7 +299,7 @@ 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': 'db3c93975a8f0851604a80e53e57f4d395d43263',
+  'shaderc_revision': 'dadf12a4bd9cb4db50922fdb2bf81fd25b40a8fc',
   # Three lines of non-changing comments so that
   # the commit queue can handle CLs rolling feed
   # and whatever else without interference from each other.