Roll src/third_party/skia/ 4e95956f1..51494f661 (6 commits)

https://skia.googlesource.com/skia.git/+log/4e95956f117f..51494f6615b8

$ git log 4e95956f1..51494f661 --date=short --no-merges --format='%ad %ae %s'
2018-01-29 halcanary SkQP: Allow checking against nearby pixel's expectations.
2018-01-30 jvanverth Reduce the amount of padding needed for SDFs, take 2
2018-01-30 halcanary SkQP: remove skia_embed_resources option
2018-01-30 angle-skia-autoroll Roll skia/third_party/externals/angle2/ 13fd988cf..513bc77df (1 commit)
2018-01-30 halcanary SkQP: slim deps.  Also skia_enable_fontmgr_empty
2018-01-29 scroggo Simplify SkAnimatedImage

Created with:
  roll-dep src/third_party/skia


The AutoRoll server is located here: https://autoroll.skia.org

Documentation for the AutoRoller is here:
https://skia.googlesource.com/buildbot/+/master/autoroll/README.md

If the roll is causing failures, please contact the current sheriff, who should
be CC'd on the roll, and stop the roller if necessary.


CQ_INCLUDE_TRYBOTS=master.tryserver.blink:linux_trusty_blink_rel;master.tryserver.chromium.linux:linux_optional_gpu_tests_rel;master.tryserver.chromium.mac:mac_optional_gpu_tests_rel;master.tryserver.chromium.win:win_optional_gpu_tests_rel
TBR=bungeman@chromium.org

Change-Id: I5d556430c393f4a57138d11aeafeeab46f0ff126
Reviewed-on: https://chromium-review.googlesource.com/894190
Commit-Queue: skia-chromium-autoroll <skia-chromium-autoroll@skia-buildbots.google.com.iam.gserviceaccount.com>
Reviewed-by: skia-chromium-autoroll <skia-chromium-autoroll@skia-buildbots.google.com.iam.gserviceaccount.com>
Cr-Commit-Position: refs/heads/master@{#533039}

DEPS

@@ -83,7 +83,7 @@ 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': '4e95956f117f8c188b565e7baefc252085b02653',
+  'skia_revision': '51494f6615b8bd637caf0fd6d0d577ea19d50948',
   # Three lines of non-changing comments so that
   # the commit queue can handle CLs rolling V8
   # and whatever else without interference from each other.