Roll src/third_party/skia/ 959fc245a..6c6ea2dab (7 commits; 1 trivial rolls)

https://skia.googlesource.com/skia.git/+log/959fc245a92a..6c6ea2dabfc8

$ git log 959fc245a..6c6ea2dab --date=short --no-merges --format='%ad %ae %s'
2018-05-10 bungeman Non-normal blur styles to work with non-a8.
2018-05-10 skcms-skia-autoroll Roll skia/third_party/skcms 5b9549a..28e8b32 (1 commits)
2018-05-10 fmalita Fix unchecked allocation in kImageFilter::Common::unflatten()
2018-05-10 egdaniel Revert "Remove guard flag for SK_SUPPORT_LEGACY_BACKEND_OBJECTS on flutter."
2018-05-10 brianosman Revert "Remove GrBackendObject and all related functions from Skia."
2018-05-10 mtklein Revert "strip down SkICC.cpp"

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;luci.chromium.try:android_optional_gpu_tests_rel;luci.chromium.try:linux_optional_gpu_tests_rel;luci.chromium.try:mac_optional_gpu_tests_rel;luci.chromium.try:win_optional_gpu_tests_rel
TBR=egdaniel@chromium.org

Change-Id: I62c06d06784d97df02150ac59ea14cf39c7e495e
Reviewed-on: https://chromium-review.googlesource.com/1054828
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@{#557755}

DEPS

@@ -96,7 +96,7 @@ 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': '959fc245a92af65fb8bb4a78db53aec188c812be',
+  'skia_revision': '6c6ea2dabfc8f4db3c469170a601dee3eb0a2bde',
   # Three lines of non-changing comments so that
   # the commit queue can handle CLs rolling V8
   # and whatever else without interference from each other.