Roll src/third_party/skia/ 4e4155df1..2796767ed (4 commits).
Roll src/third_party/skia/ 4e4155df1..2796767ed (4 commits).

https://chromium.googlesource.com/skia.git/+log/4e4155df100b..2796767eda95

$ git log 4e4155df1..2796767ed --date=short --no-merges --format='%ad %ae %s'
2015-12-14 benjaminwagner Update sync_google3.sh to match autoroller.py.
2015-12-14 bsalomon Add option to control maximum GrBatch lookback
2015-12-14 ethannicholas Switch fragment coordinate to 'highp' to fix various broken GMs.
2015-12-14 mtklein Unify some SkNx code

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

Review URL: https://codereview.chromium.org/1529483003

Cr-Commit-Position: 972c6d2dc6dd5efdad1377c0d224e03eb8f276f7@{#365143}

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