Advertise GL_EXT_disjoint_timer_query when available.
Advertise GL_EXT_disjoint_timer_query when available.

R=sievers@chromium.org
BUG=345227

Review URL: https://codereview.chromium.org/1322023003

Cr-Commit-Position: 972c6d2dc6dd5efdad1377c0d224e03eb8f276f7@{#346708}

CapOM/ChromiumGStreamerBackend,ltilve/ChromiumGStreamerBackend,ltilve/ChromiumGStreamerBackend,ltilve/ChromiumGStreamerBackend,ltilve/ChromiumGStreamerBackend,ltilve/ChromiumGStreamerBackend,CapOM/ChromiumGStreamerBackend,CapOM/ChromiumGStreamerBackend,ltilve/ChromiumGStreamerBackend,CapOM/ChromiumGStreamerBackend,CapOM/ChromiumGStreamerBackend,ltilve/ChromiumGStreamerBackend,ltilve/ChromiumGStreamerBackend,CapOM/ChromiumGStreamerBackend,CapOM/ChromiumGStreamerBackend,ltilve/ChromiumGStreamerBackend,CapOM/ChromiumGStreamerBackend,CapOM/ChromiumGStreamerBackend