Roll src/third_party/angle/ 19fa1c6f8..e8a93c6ed (3 commits)

https://chromium.googlesource.com/angle/angle.git/+log/19fa1c6f8852..e8a93c6ed6fe

$ git log 19fa1c6f8..e8a93c6ed --date=short --no-merges --format='%ad %ae %s'
2018-01-04 jdarpinian New transform feedback buffer binding rules
2018-03-08 lucferron Vulkan: Support of GL_UNSIGNED_BYTE type in drawElements
2018-03-05 brandon1.jones Add NPOT validation to copyTextureCHROMIUM

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: Ibb5aac5ef69704b80f060b2292d0480ef99d074e
Reviewed-on: https://chromium-review.googlesource.com/956891
Commit-Queue: angle-chromium-autoroll <angle-chromium-autoroll@skia-buildbots.google.com.iam.gserviceaccount.com>
Reviewed-by: angle-chromium-autoroll <angle-chromium-autoroll@skia-buildbots.google.com.iam.gserviceaccount.com>
Cr-Commit-Position: refs/heads/master@{#542040}

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': '19fa1c6f8852c54caa76b955e2e1e8e663fa8897',
+  'angle_revision': 'e8a93c6ed6feda4e0f22bd034cf95dd4aae3618d',
   # 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.