Clean up Query classes. BUG=angle:717 Change-Id: I8f29f24964a9661d9f0bea5dca48cebddbf9b0b2 Reviewed-on: https://chromium-review.googlesource.com/211136 Reviewed-by: Jamie Madill <jmadill@chromium.org> Tested-by: Shannon Woods <shannonwoods@chromium.org>