Roll Skia from ba158b9daf08 to 7839f66540b6 (3 revisions)

https://skia.googlesource.com/skia.git/+log/ba158b9daf08..7839f66540b6

2020-12-17 michaelludwig@google.com Reland "Rename getTopDevice/getDevice to topDevice/baseDevice"
2020-12-17 herb@google.com extract fibonacci allocator block code
2020-12-16 brianosman@google.com SkSL IR normalization: Convert while loops to for loops

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 tdenniston@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/+doc/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
Cq-Do-Not-Cancel-Tryjobs: true
Bug: None
Tbr: tdenniston@google.com
Change-Id: Ie21fd60324763cc1ac45bfcdec8cf48a0d2f23c0
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2596431Reviewed-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@{#837922}

DEPS

@@ -199,7 +199,7 @@ 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': 'ba158b9daf08fad6dc113297cdce1d62374e20ef',
+  'skia_revision': '7839f66540b6d5a1705bdd8817e65e7dfd4d397f',
   # Three lines of non-changing comments so that
   # the commit queue can handle CLs rolling V8
   # and whatever else without interference from each other.