Roll third_party/externals/angle2 55959b0..a8300e5 (3 commits)

https://chromium.googlesource.com/angle/angle.git/+log/55959b0bb19f..a8300e56b550


git log 55959b0..a8300e5 --date=short --no-merges --format='%ad %ae %s'
2019-03-05 courtneygo@google.com Fix scoped trace events
2019-03-05 syoussefi@chromium.org Add Orientation and Starter-Projects docs
2019-03-05 jmadill@chromium.org Use a constexpr array for es3 copy conversion table.


Created with:
  gclient setdep -r third_party/externals/angle2@a8300e56b550

The AutoRoll server is located here: https://autoroll.skia.org/r/angle-skia-autoroll

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=skia.primary:Build-Debian9-Clang-x86_64-Release-ANGLE;skia.primary:Perf-Win10-Clang-AlphaR2-GPU-RadeonR9M470X-x86_64-Debug-All-ANGLE;skia.primary:Perf-Win10-Clang-NUC5i7RYH-GPU-IntelIris6100-x86_64-Debug-All-ANGLE;skia.primary:Perf-Win10-Clang-NUC6i5SYK-GPU-IntelIris540-x86_64-Debug-All-ANGLE;skia.primary:Perf-Win10-Clang-NUCD34010WYKH-GPU-IntelHD4400-x86_64-Debug-All-ANGLE;skia.primary:Perf-Win10-Clang-ShuttleC-GPU-GTX960-x86_64-Debug-All-ANGLE;skia.primary:Test-Win10-Clang-AlphaR2-GPU-RadeonR9M470X-x86_64-Debug-All-ANGLE;skia.primary:Test-Win10-Clang-NUC6i5SYK-GPU-IntelIris540-x86_64-Debug-All-ANGLE;skia.primary:Test-Win10-Clang-NUCD34010WYKH-GPU-IntelHD4400-x86_64-Debug-All-ANGLE;skia.primary:Test-Win10-Clang-ShuttleC-GPU-GTX960-x86_64-Debug-All-ANGLE
TBR=reed@google.com

Change-Id: I221ca346be1d6bcb6cb117a533474f137e2d687a
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/198064
Reviewed-by: skia-autoroll <skia-autoroll@skia-public.iam.gserviceaccount.com>
Commit-Queue: skia-autoroll <skia-autoroll@skia-public.iam.gserviceaccount.com>

DEPS

@@ -7,7 +7,7 @@ vars = {
 deps = {
   "buildtools"                            : "https://chromium.googlesource.com/chromium/buildtools.git@505de88083136eefd056e5ee4ca0f01fe9b33de8",
   "common"                                : "https://skia.googlesource.com/common.git@9737551d7a52c3db3262db5856e6bcd62c462b92",
-  "third_party/externals/angle2"          : "https://chromium.googlesource.com/angle/angle.git@55959b0bb19f18a4dbb41656fbc95ba0b5993ce3",
+  "third_party/externals/angle2"          : "https://chromium.googlesource.com/angle/angle.git@a8300e56b550cb6f5e4bfba0e63af234d0480a88",
   "third_party/externals/dng_sdk"         : "https://android.googlesource.com/platform/external/dng_sdk.git@96443b262250c390b0caefbf3eed8463ba35ecae",
   "third_party/externals/egl-registry"    : "https://skia.googlesource.com/external/github.com/KhronosGroup/EGL-Registry@a0bca08de07c7d7651047bedc0b653cfaaa4f2ae",
   "third_party/externals/expat"           : "https://android.googlesource.com/platform/external/expat.git@android-6.0.1_r55",