Reland "Fix two issues with GLES2 devices" This is a reland of c0ed204de972c76a5428834c94aaa34fd2953329 Original change's description: > Fix two issues with GLES2 devices > > * make sure maxColorAttachments is greater than 0 > * Do not sync read buffer if maxDrawBuffers is 0 > > Bug: chromium:1167731 > Change-Id: Icd0fb5e65ec6ffdc0d6f6325ccd1207958922254 > Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/2733268 > Reviewed-by: Geoff Lang <geofflang@chromium.org> > Reviewed-by: Shahbaz Youssefi <syoussefi@chromium.org> > Commit-Queue: Peng Huang <penghuang@chromium.org> Bug: chromium:1167731 Change-Id: Iccd7b0986c4728e362fccaeda6fbeff2860d888c Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/2743665 Reviewed-by: Geoff Lang <geofflang@chromium.org> Commit-Queue: Peng Huang <penghuang@chromium.org>