This allows us to include <ostream> instead of <iostream> to avoid
including a static initializer.

BUG=angleproject:2037

Change-Id: Ib7e84a15018fa951bad1c87ffec4bfb0c896749f
Reviewed-on: https://chromium-review.googlesource.com/507627Reviewed-by: Jamie Madill <jmadill@chromium.org>
Commit-Queue: Jamie Madill <jmadill@chromium.org>