Roll SwiftShader from 87c78ac5eb86 to 421ddb40e1c1 (1 revision)

https://swiftshader.googlesource.com/SwiftShader.git/+log/87c78ac5eb86..421ddb40e1c1

2021-12-27 penghuang@chromium.org Fix swiftshader build error

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

To file a bug in SwiftShader: https://bugs.chromium.org/p/swiftshader/issues/entry
To file a bug in Dawn: https://bugs.chromium.org/p/dawn/issues/entry

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/main/autoroll/README.md

Bug: None
Tbr: enga@google.com
Change-Id: I865d6c01ab7ca68764976f05fe757188047395ee
Reviewed-on: https://dawn-review.googlesource.com/c/dawn/+/74660
Bot-Commit: Dawn Autoroller <dawn-autoroll@skia-public.iam.gserviceaccount.com>
Commit-Queue: Dawn Autoroller <dawn-autoroll@skia-public.iam.gserviceaccount.com>
diff --git a/DEPS b/DEPS
index 87e8e4c..84336df 100644
--- a/DEPS
+++ b/DEPS
@@ -121,7 +121,7 @@
   },
 
   'third_party/swiftshader': {
-    'url': '{swiftshader_git}/SwiftShader@87c78ac5eb86f1956e1b8cb987b5fceadd1d0def',
+    'url': '{swiftshader_git}/SwiftShader@421ddb40e1c105d8eeae02aa66a263e9d52fc29e',
     'condition': 'dawn_standalone',
   },