Roll src/third_party/skia ee61d3d5a3ba..55f9cba6e2e7 (2 commits)

https://skia.googlesource.com/skia.git/+log/ee61d3d5a3ba..55f9cba6e2e7

git log ee61d3d5a3ba..55f9cba6e2e7 --date=short --no-merges --format='%ad %ae %s'
2019-10-15 skia-autoroll@skia-public.iam.gserviceaccount.com Roll third_party/externals/angle2 fede5cb664d9..2d0e5b554d4f (4 commits)
2019-10-15 skia-autoroll@skia-public.iam.gserviceaccount.com Roll third_party/externals/swiftshader 1c462ebc904c..a27dfcf868bf (3 commits)

Created with:
  gclient setdep -r src/third_party/skia@55f9cba6e2e7

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 csmartdalton@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=csmartdalton@google.com

Bug: chromium:None,chromium:None
Change-Id: Ie656dbe8a4421cf76073c157106b62aaca6980b1
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1860293Reviewed-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@{#705857}

DEPS

@@ -167,7 +167,7 @@ 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': 'ee61d3d5a3baa1bbee48eb140f71afc7274978e0',
+  'skia_revision': '55f9cba6e2e7b8ff3ba4f1453349db26e547cb28',
   # Three lines of non-changing comments so that
   # the commit queue can handle CLs rolling V8
   # and whatever else without interference from each other.