Roll src/third_party/skia/ 08c4bdf30..de3aac8ce (3 commits).

https://chromium.googlesource.com/skia.git/+log/08c4bdf305b7..de3aac8cea8a

$ git log 08c4bdf30..de3aac8ce --date=short --no-merges --format='%ad %ae %s'
2015-11-22 reed use pinned value during lerp for vertical gradients
2015-11-22 halcanary SkPDF: add `final` keyword to leaf classes
2015-11-22 update-skps Update SKP version

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

Review URL: https://codereview.chromium.org/1467913002

Cr-Commit-Position: refs/heads/master@{#361054}

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': '08c4bdf305b75815cff209edcaa12b9e26690186',
+  'skia_revision': 'de3aac8cea8a7113f31591e6e02c51fe0ac45280',
   # Three lines of non-changing comments so that
   # the commit queue can handle CLs rolling V8
   # and whatever else without interference from each other.