Roll src/third_party/swiftshader a9da772f0587..04e148570dbb (8 commits)

https://swiftshader.googlesource.com/SwiftShader.git/+log/a9da772f0587..04e148570dbb

git log a9da772f0587..04e148570dbb --date=short --no-merges --format='%ad %ae %s'
2019-08-28 capn@google.com Make round-robin task enqueue index thread safe
2019-08-27 bclayton@google.com Device: Migrate Renderer to Yarn
2019-08-27 bclayton@google.com Device: Don't use a global for the cluster count.
2019-08-27 bclayton@google.com Some minor code tidying.
2019-08-27 bclayton@google.com Pipeline: Use Yarn to make compute multi-threaded.
2019-08-27 bclayton@google.com Vulkan: Build a yarn::Scheduler and pass it down to the vk::Queue.
2019-08-27 bclayton@google.com vk::Queue: Lazily construct Renderers
2019-08-27 bclayton@google.com Yarn: Don't zero-initialize data in Pool<T>::Item::construct()

Created with:
  gclient setdep -r src/third_party/swiftshader@04e148570dbb

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

CQ_INCLUDE_TRYBOTS=luci.chromium.try:android_optional_gpu_tests_rel;luci.chromium.try:linux_optional_gpu_tests_rel;luci.chromium.try:mac_optional_gpu_tests_rel;luci.chromium.try:win_optional_gpu_tests_rel
TBR=swiftshader-team+autoroll@google.com

Bug: chromium:b/139010488,chromium:b/139142453,chromium:b/139142453,chromium:b/139142453,chromium:b/139142453,chromium:b/139010488,chromium:b/139142453
Change-Id: Iceb60a95f44801f390732a1506641ace01c4e131
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1774264Reviewed-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@{#691066}

DEPS

@@ -178,7 +178,7 @@ vars = {
   # Three lines of non-changing comments so that
   # the commit queue can handle CLs rolling SwiftShader
   # and whatever else without interference from each other.
-  'swiftshader_revision': 'a9da772f0587a3b1dd789dad3d1846c9e5769771',
+  'swiftshader_revision': '04e148570dbb420409ce9212f2e8c03e675bea48',
   # Three lines of non-changing comments so that
   # the commit queue can handle CLs rolling PDFium
   # and whatever else without interference from each other.