Roll src/third_party/skia/ b3cb21427..426a24592 (2 commits).

https://chromium.googlesource.com/skia.git/+log/b3cb2142725f..426a2459290a

$ git log b3cb21427..426a24592 --date=short --no-merges --format='%ad %ae %s'
2016-09-08 halcanary SkPDF: hand SfntlyWrapper::SubsetFont() ttcIndex, not fontName.
2016-09-08 kjlubick Fix strange failures on Android N

CQ_INCLUDE_TRYBOTS=master.tryserver.blink:linux_precise_blink_rel
TBR=caryclark@google.com

Review-Url: https://codereview.chromium.org/2326783003
Cr-Commit-Position: refs/heads/master@{#417476}

DEPS

@@ -36,7 +36,7 @@ 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': 'b3cb2142725f9d0cd88a7200770536bc21f73b14',
+  'skia_revision': '426a2459290a57bf32151f042fe5cd67da61d02f',
   # Three lines of non-changing comments so that
   # the commit queue can handle CLs rolling V8
   # and whatever else without interference from each other.