Roll src/third_party/skia/ a42405aa5..55bcc8e0a (2 commits).

https://chromium.googlesource.com/skia.git/+log/a42405aa522c..55bcc8e0af34

$ git log a42405aa5..55bcc8e0a --date=short --no-merges --format='%ad %ae %s'
2016-09-09 msarett Delete some LUTs from SkColorSpaceXform
2016-09-09 caryclark fix fuzzer

BUG=644680,644684

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

Review-Url: https://codereview.chromium.org/2325133003
Cr-Commit-Position: refs/heads/master@{#417595}

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': 'a42405aa522cd33292b9817da460e9f29e00a201',
+  'skia_revision': '55bcc8e0af3415601b3d62252a0d579fbe87c85a',
   # Three lines of non-changing comments so that
   # the commit queue can handle CLs rolling V8
   # and whatever else without interference from each other.