Roll src/third_party/skia/ b461d3457..7e68ab731 (3 commits).
Roll src/third_party/skia/ b461d3457..7e68ab731 (3 commits).

https://chromium.googlesource.com/skia.git/+log/b461d3457567..7e68ab73186a

$ git log b461d3457..7e68ab731 --date=short --no-merges --format='%ad %ae %s'
2016-04-13 bsalomon Remove GrTextureStorageAllocator. This was added from Chromium but never used and not expected to be used. GOLD_TRYBOT_URL= https://gold.skia.org/search2?unt=true&query=source_type%3Dgm&master=false&issue=1886613003
2016-04-13 brianosman Tweak distance field path renderer behavior in gamma-correct mode to match recent changes to text rendering.
2016-04-13 bungeman Respect FC_MATRIX and FC_EMBOLDEN as extra font parameters.

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

Review URL: https://codereview.chromium.org/1888453003

Cr-Commit-Position: 972c6d2dc6dd5efdad1377c0d224e03eb8f276f7@{#387141}

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