Roll src/third_party/skia/ 56a11e4d6..c2878e23d (4 commits).
Roll src/third_party/skia/ 56a11e4d6..c2878e23d (4 commits).

https://chromium.googlesource.com/skia.git/+log/56a11e4d6f3d..c2878e23d405

$ git log 56a11e4d6..c2878e23d --date=short --no-merges --format='%ad %ae %s'
2016-05-17 bsalomon Remove GrFontScaler class.
2016-05-17 liyuqian Implement touch control
2016-05-17 msarett Fix leak of SkGammas
2016-05-17 bungeman Fix code guarded by SK_FONT_HOST_USE_SYSTEM_SETTINGS.

BUG=608566

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

Review-Url: https://codereview.chromium.org/1992463003
Cr-Commit-Position: 972c6d2dc6dd5efdad1377c0d224e03eb8f276f7@{#394305}

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