Roll Skia from 4c89481be495 to 1b1c73ad500b (2 revisions)

https://skia.googlesource.com/skia.git/+log/4c89481be495..1b1c73ad500b

2021-01-20 bungeman@google.com Remove deprecated SkBase64 interface.
2021-01-20 ethannicholas@google.com Refactored SkSL convertVarDeclaration to make it more accessible from

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 scroggo@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
Cq-Do-Not-Cancel-Tryjobs: true
Bug: None
Tbr: scroggo@google.com
Change-Id: Ib666b52b7072cac9531a9221b13699dd22e773e9
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2639937Reviewed-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@{#845311}

DEPS

@@ -199,7 +199,7 @@ 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': '4c89481be4957cb943d2545793b0b41d1ee557d8',
+  'skia_revision': '1b1c73ad500b25aa16ec333a175796514a77978c',
   # Three lines of non-changing comments so that
   # the commit queue can handle CLs rolling V8
   # and whatever else without interference from each other.