Roll src/third_party/skia/ fea7de6c1..235cbf23c (4 commits).
Roll src/third_party/skia/ fea7de6c1..235cbf23c (4 commits).

https://chromium.googlesource.com/skia.git/+log/fea7de6c1459..235cbf23c483

$ git log fea7de6c1..235cbf23c --date=short --no-merges --format='%ad %ae %s'
2016-04-05 brianosman Create output directory in skdiff
2016-04-05 bsalomon Rename enums in GrContextFactory to remove "GL"
2016-04-05 egdaniel Fix vulkan dual source blending
2016-04-05 bsalomon Remove 'native' context unit test macro.

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

Review URL: https://codereview.chromium.org/1858373002

Cr-Commit-Position: 972c6d2dc6dd5efdad1377c0d224e03eb8f276f7@{#385268}

axinging/chromium-crosswalk,axinging/chromium-crosswalk,axinging/chromium-crosswalk,axinging/chromium-crosswalk,axinging/chromium-crosswalk,axinging/chromium-crosswalk,axinging/chromium-crosswalk,axinging/chromium-crosswalk,axinging/chromium-crosswalk,axinging/chromium-crosswalk,axinging/chromium-crosswalk