Several query methods simply wrapped a NULL check with a default
return value. Most of these safety checks were unnecessary.

BUG=angle:660

Change-Id: I0ac6897f06be082c8efab8721920d1b51ba999ee
Reviewed-on: https://chromium-review.googlesource.com/205606Reviewed-by: Geoff Lang <geofflang@chromium.org>
Tested-by: Jamie Madill <jmadill@chromium.org>