Roll src/third_party/skia/ b30d11319..b437351d8 (3 commits)

https://skia.googlesource.com/skia.git/+log/b30d11319bac..b437351d880f

$ git log b30d11319..b437351d8 --date=short --no-merges --format='%ad %ae %s'
2017-10-02 mtklein add _skx stages
2017-10-02 brianosman Revert^6 "Make threaded proxy generation MDB-friendly, and defer instantiation"
2017-10-02 enne Fix SkRRect validation for negative types

Created with:
  roll-dep src/third_party/skia


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

If the roll is causing failures, see:
http://www.chromium.org/developers/tree-sheriffs/sheriff-details-chromium#TOC-Failures-due-to-DEPS-rolls


CQ_INCLUDE_TRYBOTS=master.tryserver.blink:linux_trusty_blink_rel;master.tryserver.chromium.linux:linux_optional_gpu_tests_rel;master.tryserver.chromium.mac:mac_optional_gpu_tests_rel;master.tryserver.chromium.win:win_optional_gpu_tests_rel;master.tryserver.chromium.android:android_optional_gpu_tests_rel
TBR=scroggo@chromium.org

Change-Id: I86775b2a57fdabedb95053ea5a7aadc7eb4cf30a
Reviewed-on: https://chromium-review.googlesource.com/696128Reviewed-by: Skia Deps Roller <skia-deps-roller@chromium.org>
Commit-Queue: Skia Deps Roller <skia-deps-roller@chromium.org>
Cr-Commit-Position: refs/heads/master@{#505906}

DEPS

@@ -45,7 +45,7 @@ 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': 'b30d11319bac8bb7a528b6da5ddd13ac9db26996',
+  'skia_revision': 'b437351d880fd17ea2bb8fd0997da7754a32903c',
   # Three lines of non-changing comments so that
   # the commit queue can handle CLs rolling V8
   # and whatever else without interference from each other.