Roll SwiftShader from 4615971566e1 to 763957e6b4fc (2 revisions)

https://swiftshader.googlesource.com/SwiftShader.git/+log/4615971566e1..763957e6b4fc

2020-06-17 capn@google.com Ignore rasterization state pointers when rasterization is disabled
2020-06-17 capn@google.com Zero-initialize the context state and data

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/+doc/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;luci.chromium.try:linux-swangle-try-x64;luci.chromium.try:win-swangle-try-x86
Bug: None
Tbr: swiftshader-team+autoroll@google.com
Change-Id: If501e80eb87d8ff218cae5cae5c84e226f7c05d6
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2246274Reviewed-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@{#779162}

DEPS

@@ -198,7 +198,7 @@ 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': '4615971566e13b5a6bb741874d4de4d768d18794',
+  'swiftshader_revision': '763957e6b4fc1aa360ab19c4109b8b26686783e8',
   # Three lines of non-changing comments so that
   # the commit queue can handle CLs rolling PDFium
   # and whatever else without interference from each other.