Roll src/third_party/skia bc73eb4fcc89..df2c1ee4f270 (2 commits)

https://skia.googlesource.com/skia.git/+log/bc73eb4fcc89..df2c1ee4f270

git log bc73eb4fcc89..df2c1ee4f270 --date=short --first-parent --format='%ad %ae %s'
2019-12-27 herb@google.com Simplify color and translate updates
2019-12-27 halcanary@google.com GrGLMakeNativeInterface_{iOS,mac,win}: clean up

Created with:
  gclient setdep -r src/third_party/skia@df2c1ee4f270

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 fmalita@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
Bug: None
Tbr: fmalita@google.com
Change-Id: Ia141922bf62394e9c6196076c72a5de546255df9
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1983186Reviewed-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@{#727584}

DEPS

@@ -175,7 +175,7 @@ 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': 'bc73eb4fcc89a94b972232a2a66e38777085ffb9',
+  'skia_revision': 'df2c1ee4f2701957498a225a58d2d2df23f90113',
   # Three lines of non-changing comments so that
   # the commit queue can handle CLs rolling V8
   # and whatever else without interference from each other.