Roll src/third_party/swiftshader cb9bf9ac9dc2..2568cf76ee2c (4 commits)

https://swiftshader.googlesource.com/SwiftShader.git/+log/cb9bf9ac9dc2..2568cf76ee2c


git log cb9bf9ac9dc2..2568cf76ee2c --date=short --no-merges --format='%ad %ae %s'
2019-05-10 bclayton@google.com SpirvShader: Implement OpImageQuerySamples
2019-05-10 bclayton@google.com Assign the DeviceIndex builtIn (ext: SPV_KHR_device_group).
2019-05-10 bclayton@google.com SpirvShader: Fix incorrect use of getPointer() with GetPointerToData()
2019-05-10 bclayton@google.com SpirvShader: Implement OpImageQueryLevels


Created with:
  gclient setdep -r src/third_party/swiftshader@2568cf76ee2c

The AutoRoll server is located here: https://autoroll.skia.org/r/swiftshader-chromium-autoroll

Documentation for the AutoRoller is here:
https://skia.googlesource.com/buildbot/+/master/autoroll/README.md

If the roll is causing failures, please contact the current sheriff, who should
be CC'd on the roll, and stop the roller if necessary.

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

BUG=chromium:b/129523279,chromium:b/130937460,chromium:b/129523279
TBR=swiftshader-team+autoroll@google.com

Change-Id: I8c3ca554c5c2466d96f7e1435ab7a1ae9b9a44a8
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1606077Reviewed-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@{#658730}

DEPS

@@ -149,7 +149,7 @@ 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': 'cb9bf9ac9dc258dc1eabd4fca78a9901a51c74c8',
+  'swiftshader_revision': '2568cf76ee2c21dac908ae94aebbeae715c6faef',
   # Three lines of non-changing comments so that
   # the commit queue can handle CLs rolling PDFium
   # and whatever else without interference from each other.