Roll src/third_party/skia/ 8ffab6fc0..0b55664af (8 commits).

https://chromium.googlesource.com/skia.git/+log/8ffab6fc0eff..0b55664afc85

$ git log 8ffab6fc0..0b55664af --date=short --no-merges --format='%ad %ae %s'
2016-04-26 msarett Update SK_IMAGE_VERSION, run nanobench on its own image set
2016-04-26 msarett Remove redundant tests to make DM a little faster
2016-04-26 msarett Remove redundant test
2016-04-26 bsalomon Add initial implementation of GrShape and GrStyle classes and tests
2016-04-26 liyuqian Add runhooks to multi_repo_trybots
2016-04-26 halcanary pdf comparison tool
2016-04-26 djsollen Update android docs for how to sync source code GOLD_TRYBOT_URL= https://gold.skia.org/search2?unt=true&query=source_type%3Dgm&master=false&issue=1921023002 NOTRY=true DOCS_PREVIEW= https://skia.org/?cl=1921023002
2016-04-26 halcanary bin/fetch-skps: print instruction on error

CQ_INCLUDE_TRYBOTS=tryserver.blink:linux_blink_rel
TBR=stephana@google.com

Review URL: https://codereview.chromium.org/1914273002

Cr-Commit-Position: refs/heads/master@{#389908}

DEPS

@@ -39,7 +39,7 @@ 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': '8ffab6fc0effa9b467584bf3bf9d7d0345e2aeb9',
+  'skia_revision': '0b55664afc854b03082c467505b1a811721bcd7a',
   # Three lines of non-changing comments so that
   # the commit queue can handle CLs rolling V8
   # and whatever else without interference from each other.