Roll src/third_party/skia/ c6912f712..1bfece855 (18 commits; 1 trivial rolls)

https://skia.googlesource.com/skia.git/+log/c6912f712f34..1bfece8556cc

$ git log c6912f712..1bfece855 --date=short --no-merges --format='%ad %ae %s'
2017-06-01 robertphillips Rm int flavor of GrNextPow2 in favor of uint32_t flavor
2017-06-01 kjlubick Use ssh to trigger chromecast test
2017-06-01 lsalzman fix premultiplied color generation in linear gradients when using fApplyAlphaAfterInterp
2017-06-01 mtklein have shaders that need seed_shader call it themselves
2017-05-31 recipe-roller Roll recipe dependencies (nontrivial).
2017-06-01 mtklein plumb y through to SkJumper
2017-06-01 jcgregorio [fiddle] Report GL driver info.
2017-06-01 brianosman Revert "Expand texturability testing to cover mip-mapped textures, and fix iOS"
2017-06-01 brianosman Expand texturability testing to cover mip-mapped textures, and fix iOS
2017-06-01 mtklein update SkRasterPipeline::run() to also take y
2017-05-26 msarett Better image for copyTo4444 test
2017-06-01 brianosman Revert "Expand texturability testing to cover mip-mapped textures, and fix iOS"
2017-06-01 fmalita Add smartptr SkRWBuffer snapshot methods
2017-06-01 robertphillips Update copyOp to split-opList world
2017-06-01 brianosman Expand texturability testing to cover mip-mapped textures, and fix iOS
2017-06-01 robertphillips update GrOp printouts
2017-05-31 mtklein raster pipeline sprite blitter

Created with:
  roll-dep src/third_party/skia


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=herb@chromium.org

Change-Id: I190f25b47a967af5fb7466f0471616e2feba34e9
Reviewed-on: https://chromium-review.googlesource.com/521705Reviewed-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@{#476461}

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': 'c6912f712f3423b2a09a6e96c999b65a1fd86062',
+  'skia_revision': '1bfece8556cc03b6aa904b2445d2332136bce037',
   # Three lines of non-changing comments so that
   # the commit queue can handle CLs rolling V8
   # and whatever else without interference from each other.