Use angle::FastVector in ImageEGL::initialize to avoid heap allocation Bug: chromium:1336126 Change-Id: I40349c618b648f3a96c19b2f2b032275af90086b Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/3812564 Auto-Submit: Peng Huang <penghuang@chromium.org> Commit-Queue: Shahbaz Youssefi <syoussefi@chromium.org> Reviewed-by: Shahbaz Youssefi <syoussefi@chromium.org>