Roll src/third_party/skia a979b28cbbd0..7697476ad2d7 (2 commits)

https://skia.googlesource.com/skia.git/+log/a979b28cbbd0..7697476ad2d7

git log a979b28cbbd0..7697476ad2d7 --date=short --no-merges --format='%ad %ae %s'
2019-10-25 emircan@google.com Disable async readback from protected memory
2019-10-25 herb@google.com Change from single prepareForDrawing to prepare[Mask|SDFT|Path]ForDrawing

Created with:
  gclient setdep -r src/third_party/skia@7697476ad2d7

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 michaelludwig@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=michaelludwig@google.com

Bug: None
Change-Id: I8267e41f72318c92420fab0eec8837100662bb25
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1881113Reviewed-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@{#709657}

DEPS

@@ -171,7 +171,7 @@ 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': 'a979b28cbbd004225ca65a42de0aa9593252dd98',
+  'skia_revision': '7697476ad2d71a0402c1f181ec9c7ab557544edc',
   # Three lines of non-changing comments so that
   # the commit queue can handle CLs rolling V8
   # and whatever else without interference from each other.