Frontend support for QCOM foveated extensions Add frontend state management to support foveated rendering extensions. Bug: angleproject:8484 Test: Texture2D*Foveation* Change-Id: I0e1be9f11b2d442207674562da760f5bfd7debc8 Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/5208091 Reviewed-by: Shahbaz Youssefi <syoussefi@chromium.org> Commit-Queue: mohan maiya <m.maiya@samsung.com> Reviewed-by: Geoff Lang <geofflang@chromium.org>