Roll src/third_party/skia db2e7641bed8..b6b7e7b6c8de (5 commits)

https://skia.googlesource.com/skia.git/+log/db2e7641bed8..b6b7e7b6c8de

git log db2e7641bed8..b6b7e7b6c8de --date=short --first-parent --format='%ad %ae %s'
2019-12-03 mtklein@google.com Revert "replace SkColorSpaceXformSteps::Required()"
2019-12-03 fmalita@chromium.org [skottie] Remove defensive seek(0) from Animation ctor
2019-12-03 mtklein@google.com Fix some GCC warnings.
2019-12-03 reed@google.com remove legacy next from iter
2019-12-03 kjlubick@google.com [canvaskit] Add test and extern for MakeImage

Created with:
  gclient setdep -r src/third_party/skia@b6b7e7b6c8de

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 bsalomon@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: bsalomon@google.com
Change-Id: I37739ac1c744a36fce9939d4052e6612c999d855
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1949023Reviewed-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@{#721102}

DEPS

@@ -172,7 +172,7 @@ 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': 'db2e7641bed8cfb172689eb92344ec6edb2b8856',
+  'skia_revision': 'b6b7e7b6c8de74acb9dbb5b636634e20a27bcdaa',
   # Three lines of non-changing comments so that
   # the commit queue can handle CLs rolling V8
   # and whatever else without interference from each other.