Roll Skia from 19c3850508fd to 2c4a07d925cc (8 revisions)

https://skia.googlesource.com/skia.git/+log/19c3850508fd..2c4a07d925cc

2020-08-06 nifong@google.com allow external files in canvas_perf.js tests
2020-08-06 robertphillips@google.com Fix parameter evaluation order bug in DDLPromiseImageHelper
2020-08-06 johnstiles@google.com Update the DitherEffect @test to ensure non-zero dithering.
2020-08-06 jvanverth@google.com Fix unaligned pointer warning on iOS.
2020-08-06 johnstiles@google.com Implement matrix casting in Metal.
2020-08-06 ethannicholas@google.com simplified SkSL REHYDRATE=0
2020-08-06 johnstiles@google.com Enable ClangTidy check llvm-namespace-comment.
2020-08-06 brianosman@google.com SkRuntimeEffect: Apply uniform transforms in color filters, too

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 herb@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: herb@google.com
Change-Id: I531ff3557e4fed430161fc54970bc4d3d741c87a
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2341698Reviewed-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@{#795700}

DEPS

@@ -195,7 +195,7 @@ 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': '19c3850508fd257addbf8efb75d56e28c62585ca',
+  'skia_revision': '2c4a07d925cca715a6790aa64da0ecf3c02d2810',
   # Three lines of non-changing comments so that
   # the commit queue can handle CLs rolling V8
   # and whatever else without interference from each other.