Roll src/third_party/skia 6ed3e8e779e4..c25802db30fa (5 commits)

https://skia.googlesource.com/skia.git/+log/6ed3e8e779e4..c25802db30fa

git log 6ed3e8e779e4..c25802db30fa --date=short --no-merges --format='%ad %ae %s'
2019-09-16 jvanverth@google.com Add ETC2 support to Metal backend.
2019-09-16 brianosman@google.com Particle effect scripting update
2019-09-16 recipe-mega-autoroller@chops-service-accounts.iam.gserviceaccount.com Roll recipe dependencies (trivial).
2019-09-16 brianosman@google.com Fix precompiling shaders on GLES / Android
2019-09-16 recipe-mega-autoroller@chops-service-accounts.iam.gserviceaccount.com Roll recipe dependencies (trivial).

Created with:
  gclient setdep -r src/third_party/skia@c25802db30fa

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 brianosman@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/+/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
TBR=brianosman@google.com

Bug: None
Change-Id: I9a6d38e7c909354a79333c129c8bc1cd21655f1a
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1804585Reviewed-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@{#696922}

DEPS

@@ -162,7 +162,7 @@ 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': '6ed3e8e779e402de93347df4d205dc220624d97e',
+  'skia_revision': 'c25802db30fa371d3984eeef6b04a605e7b7f51f',
   # Three lines of non-changing comments so that
   # the commit queue can handle CLs rolling V8
   # and whatever else without interference from each other.