Implement swapInterval for EGL on GLX BUG=angleproject:892 Change-Id: I80d8d67270662c7f2be893f4a8318fbc0926f1fc Reviewed-on: https://chromium-review.googlesource.com/272677 Reviewed-by: Jamie Madill <jmadill@chromium.org> Reviewed-by: Geoff Lang <geofflang@chromium.org> Tested-by: Corentin Wallez <cwallez@chromium.org>