Roll src/third_party/angle/ 5164b797c..5242d5bf7 (2 commits)

https://chromium.googlesource.com/angle/angle.git/+log/5164b797cb91..5242d5bf74d3

$ git log 5164b797c..5242d5bf7 --date=short --no-merges --format='%ad %ae %s'
2018-02-15 lucferron Vulkan: Implement scissored clears.
2018-03-08 jmadill Return errors from gl::State::syncDirtyObjects.

Created with:
  roll-dep src/third_party/angle


The AutoRoll server is located here: https://angle-chromium-roll.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.chromium.android:android_optional_gpu_tests_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=ynovikov@chromium.org

Change-Id: Ie979cff7e2ed47e4203af9656e35e8b406346bb8
Reviewed-on: https://chromium-review.googlesource.com/955935Reviewed-by: angle-chromium-autoroll <angle-chromium-autoroll@skia-buildbots.google.com.iam.gserviceaccount.com>
Commit-Queue: angle-chromium-autoroll <angle-chromium-autoroll@skia-buildbots.google.com.iam.gserviceaccount.com>
Cr-Commit-Position: refs/heads/master@{#541846}

DEPS

@@ -91,7 +91,7 @@ vars = {
   # Three lines of non-changing comments so that
   # the commit queue can handle CLs rolling ANGLE
   # and whatever else without interference from each other.
-  'angle_revision': '5164b797cb9180cc0b18543e08abc7328feff1aa',
+  'angle_revision': '5242d5bf74d38269605141c9f1cb23d51ab77e1e',
   # Three lines of non-changing comments so that
   # the commit queue can handle CLs rolling build tools
   # and whatever else without interference from each other.