Roll SwiftShader from 3549479dc4cc to 5255c465bbba (6 revisions)

https://swiftshader.googlesource.com/SwiftShader.git/+log/3549479dc4cc..5255c465bbba

2021-01-14 swiftshader.regress@gmail.com Regres: Update test lists @ 2cc34907
2021-01-13 amaiorano@google.com VulkanBenchmarks: add texture sampling to Triangle benchmarks
2021-01-13 amaiorano@google.com Implement VK_EXT_headless_surface
2021-01-13 natsu@google.com Update AHB default YUV dataspace to YCBCR_601
2021-01-13 capn@google.com VulkanBenchmarks: refactor into Image class
2021-01-13 capn@google.com Fix back-face culling for vertices near w=0

If this roll has caused a breakage, revert this CL and stop the roller
using the controls here:
https://autoroll.skia.org/r/swiftshader-skia-autoroll
Please CC ethannicholas@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

Cq-Include-Trybots: skia/skia.primary:Test-Debian10-Clang-GCE-GPU-SwiftShader-x86_64-Debug-All-SwiftShader
Bug: None
Tbr: ethannicholas@google.com
Change-Id: I6889acc69a2d9464fac7bc62db4b6755440be897
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/353512
Reviewed-by: skia-autoroll <skia-autoroll@skia-public.iam.gserviceaccount.com>
Commit-Queue: skia-autoroll <skia-autoroll@skia-public.iam.gserviceaccount.com>
diff --git a/DEPS b/DEPS
index 01ed88b..122c8b4 100644
--- a/DEPS
+++ b/DEPS
@@ -40,7 +40,7 @@
   "third_party/externals/spirv-cross"     : "https://chromium.googlesource.com/external/github.com/KhronosGroup/SPIRV-Cross@bdbef7b1f3982fe99a62d076043036abe6dd6d80",
   "third_party/externals/spirv-headers"   : "https://skia.googlesource.com/external/github.com/KhronosGroup/SPIRV-Headers.git@c0df742ec0b8178ad58c68cff3437ad4b6a06e26",
   "third_party/externals/spirv-tools"     : "https://skia.googlesource.com/external/github.com/KhronosGroup/SPIRV-Tools.git@e95fbfb1f509ad7a7fdfb72ac35fe412d72fc4a4",
-  "third_party/externals/swiftshader"     : "https://swiftshader.googlesource.com/SwiftShader@3549479dc4ccd92ef3b9e179080dcec1a430b01d",
+  "third_party/externals/swiftshader"     : "https://swiftshader.googlesource.com/SwiftShader@5255c465bbbab020b2fa98f818a705e764865869",
   #"third_party/externals/v8"              : "https://chromium.googlesource.com/v8/v8.git@5f1ae66d5634e43563b2d25ea652dfb94c31a3b4",
   "third_party/externals/wuffs"           : "https://skia.googlesource.com/external/github.com/google/wuffs.git@00cc8a50aa0c86b6bcb37e9ece8fb100047cc17b",
   "third_party/externals/zlib"            : "https://chromium.googlesource.com/chromium/src/third_party/zlib@eaf99a4e2009b0e5759e6070ad1760ac1dd75461",