Roll src/third_party/skia/ 7516c2775..249ee1f98 (10 commits)

https://skia.googlesource.com/skia.git/+log/7516c2775c30..249ee1f985b4

$ git log 7516c2775..249ee1f98 --date=short --no-merges --format='%ad %ae %s'
2017-08-01 mtklein clamp to 0 in repeat and mirror image tilers
2017-08-01 brianosman Guard against D3D NaN/Infinity literals bug
2017-08-01 ethannicholas support for 'half' types in sksl, plus general numeric type improvements
2017-08-01 bungeman Assert text passed to canvas is initialized.
2017-08-01 mtklein Add Perf-Win2k8-Clang bots.
2017-08-01 liyuqian Revert "Revert "Revert "Add support for semaphores to be inserted on GrContext flush"""
2017-08-01 bsalomon Allow RegionOp to be used for stenciling
2017-08-01 brianosman Remove unused code for index 8
2017-08-01 robertphillips Roll ANGLE
2017-08-01 egdaniel Revert "Revert "Add support for semaphores to be inserted on GrContext flush""

Created with:
  roll-dep src/third_party/skia
BUG=749260,750070,750071,750072


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

If the roll is causing failures, see:
http://www.chromium.org/developers/tree-sheriffs/sheriff-details-chromium#TOC-Failures-due-to-DEPS-rolls


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;master.tryserver.chromium.android:android_optional_gpu_tests_rel
TBR=liyuqian@chromium.org

Change-Id: I7026762d2d4d4c8423e909c82f6f0216f5aaebb1
Reviewed-on: https://chromium-review.googlesource.com/596829Reviewed-by: Skia Deps Roller <skia-deps-roller@chromium.org>
Commit-Queue: Skia Deps Roller <skia-deps-roller@chromium.org>
Cr-Commit-Position: refs/heads/master@{#491127}

DEPS

@@ -40,7 +40,7 @@ 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': '7516c2775c30d04a8d2c467f18d3289d78c2b841',
+  'skia_revision': '249ee1f985b4bad78db2d5cfdd14ce38edb2c23a',
   # Three lines of non-changing comments so that
   # the commit queue can handle CLs rolling V8
   # and whatever else without interference from each other.