Roll src/third_party/skia bacb821c428a..5b218519a4b1 (3 commits)

https://skia.googlesource.com/skia.git/+log/bacb821c428a..5b218519a4b1

git log bacb821c428a..5b218519a4b1 --date=short --no-merges --format='%ad %ae %s'
2019-08-15 michaelludwig@google.com Add helpers for creating new contexts
2019-08-15 rmistry@google.com [perf_skottiewasm_lottieweb] Increase loops to 5
2019-08-15 ethannicholas@google.com unified Metal uniform buffers

Created with:
  gclient setdep -r src/third_party/skia@5b218519a4b1

The AutoRoll server is located here: https://autoroll.skia.org/r/skia-autoroll

Documentation for the AutoRoller is here:
https://skia.googlesource.com/buildbot/+/master/autoroll/README.md

If the roll is causing failures, please contact the current sheriff, who should
be CC'd on the roll, and stop the roller if necessary.


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=scroggo@google.com

Bug: None
Change-Id: Ib29cade4f7abc17fd0ab973b8e636cc85ac0c8b2
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1756445Reviewed-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@{#687365}

DEPS

@@ -145,7 +145,7 @@ 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': 'bacb821c428ac51db0ca3234565dba41a327adb7',
+  'skia_revision': '5b218519a4b19e222630ac389f55cf84878a5f24',
   # Three lines of non-changing comments so that
   # the commit queue can handle CLs rolling V8
   # and whatever else without interference from each other.