Roll Skia from c950e05bafcd to 304dfa379c54 (8 revisions)

https://skia.googlesource.com/skia.git/+log/c950e05bafcd..304dfa379c54

2020-06-18 brianosman@google.com Remove swizzling-store instructions from SkSL ByteCode
2020-06-18 fmalita@chromium.org [skottie] Add support for unprefixed valign/resizing props
2020-06-18 bsalomon@google.com Use child texture effects in ProcessorRefTest
2020-06-18 johnstiles@google.com Roll gn.
2020-06-18 fmalita@chromium.org [skrive] Start parsing the node hierarchy
2020-06-18 brianosman@google.com Remove swizzling-load instructions from SkSL ByteCode
2020-06-18 brianosman@google.com In SkSLSlide, directly use Viewer's shader error handler
2020-06-18 mtklein@google.com allow fallback to skvm blitter

If this roll has caused a breakage, revert this CL and stop the roller
using the controls here:
https://autoroll.skia.org/r/skia-autoroll
Please CC djsollen@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-blink-rel;luci.chromium.try:linux-chromeos-compile-dbg;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: djsollen@google.com
Change-Id: Icc61f224925aaacf2fa9e43cff384346a3298f06
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2252535Reviewed-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@{#780082}

DEPS

@@ -182,7 +182,7 @@ vars = {
   # Three lines of non-changing comments so that
   # the commit queue can handle CLs rolling Skia
   # and whatever else without interference from each other.
-  'skia_revision': 'c950e05bafcdec649c81165214a9bb031d57ebea',
+  'skia_revision': '304dfa379c5421648ad582ab3256f86d062969ab',
   # Three lines of non-changing comments so that
   # the commit queue can handle CLs rolling V8
   # and whatever else without interference from each other.