Roll src/third_party/swiftshader 7a15cef26d94..d00dfe493098 (9 commits)

https://swiftshader.googlesource.com/SwiftShader.git/+log/7a15cef26d94..d00dfe493098

git log 7a15cef26d94..d00dfe493098 --date=short --first-parent --format='%ad %ae %s'
2019-12-09 chrisforbes@google.com Remove Float->UInt conversion workaround
2019-12-09 capn@google.com Add Float to UInt unit test
2019-12-09 amaiorano@google.com Add REACTOR_DEFAULT_OPT_LEVEL macro
2019-12-09 amaiorano@google.com Subzero: fix alloca return address allocation
2019-12-09 amaiorano@google.com Subzero: proper fix for assert(Dest->hasReg())
2019-12-09 bclayton@google.com CMakeLists: Add CMake rules for Vulkan debugger
2019-12-09 bclayton@google.com Add github.com/google/cppdap as a third_party dependency
2019-12-09 bclayton@google.com Add github.com/nlohmann/json as a third_party dependency
2019-12-09 capn@google.com Enforce int and short to be 32- and 16-bit respectively

Created with:
  gclient setdep -r src/third_party/swiftshader@d00dfe493098

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_chromium_msan_rel_ng;luci.chromium.try:linux_optional_gpu_tests_rel;luci.chromium.try:mac_optional_gpu_tests_rel;luci.chromium.try:win_optional_gpu_tests_rel
Bug: None
Tbr: swiftshader-team+autoroll@google.com
Change-Id: Icdf19cf41ce49597c83af892f156cf7aec045487
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1958619Reviewed-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@{#723267}

DEPS

@@ -188,7 +188,7 @@ 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': '7a15cef26d941478d89ba79cca761fdbeaff78e0',
+  'swiftshader_revision': 'd00dfe49309846e635252162d73c1c45933e8073',
   # Three lines of non-changing comments so that
   # the commit queue can handle CLs rolling PDFium
   # and whatever else without interference from each other.