Roll ANGLE.

746d0ea..8e7c8a
https://chromium.googlesource.com/angle/angle/+log/746d0ea..8e7c8a

BUG=434033

Review URL: https://codereview.chromium.org/785543003

Cr-Commit-Position: refs/heads/master@{#307087}

DEPS

@@ -60,7 +60,7 @@ 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": "746d0ea79208b514e95e626310bec513fa666ca4",
+  "angle_revision": "8e7c8a13791d5e0cb503898d5a7d1f38471deb69",
   # 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.