Roll src/third_party/angle/ eb79e337c..427064d2a (8 commits)

https://chromium.googlesource.com/angle/angle.git/+log/eb79e337c9f7..427064d2ac0b

$ git log eb79e337c..427064d2a --date=short --no-merges --format='%ad %ae %s'
2018-04-13 jmadill Fix perf regression with checkStatus.
2018-04-10 courtneygo Vulkan: Add build toggle for validation layers.
2018-04-17 jmadill Optimize ValidateDrawAttribs: Part 2.
2018-04-16 lucferron Vulkan: Use SH_INITIALIZE_UNINITIALIZED_LOCALS in ShaderVk
2018-04-16 lucferron Vulkan: Implement depth_range dirty bit and enable tests
2018-04-16 lucferron Vulkan: Fix the issue with unused attributes / varyings
2018-04-18 lucferron Vulkan: Fix issue in GlslWrapper and maxVaryingVectors calculation (2nd try)
2018-04-13 oetuaho Refactor GL tests to use a shader library

Created with:
  roll-dep src/third_party/angle
BUG=chromium:822235


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=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=jmadill@chromium.org

Change-Id: I99521579232a65d62698e7c4f73aa0b697f219fc
Reviewed-on: https://chromium-review.googlesource.com/1017318
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@{#551792}

DEPS

@@ -98,7 +98,7 @@ 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': 'eb79e337c9f7b2bf2d8c9a7f3298f77bf484d18a',
+  'angle_revision': '427064d2ac0bdd008cc259bb865d9d13cd7eeced',
   # 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.