Chrome needs this extension to be exposed to load the query entry points,
even for emulated query types.

BUG=angleproject:2855

Change-Id: I09dbb45c391df64d67858f9131c45b164947a707
Reviewed-on: https://chromium-review.googlesource.com/1255507Reviewed-by: Shahbaz Youssefi <syoussefi@chromium.org>
Commit-Queue: Geoff Lang <geofflang@chromium.org>