Merge pull request #1067 from Manishearth/document-visibility

Change document visibility check to be UA choice

index.bs

@@ -2349,7 +2349,6 @@ To determine if <dfn>poses must be limited</dfn> between two spaces, |space| and
   1. If either |space| or |baseSpace| are an {{XRBoundedReferenceSpace}} and the other space's [=native origin=]'s falls further outside the [=native bounds geometry=] than a reasonable distance determined by the user agent, return true.
   1. If either |space| or |baseSpace| are an {{XRReferenceSpace}} with a [=XRReferenceSpace/type=] of {{XRReferenceSpaceType/"local"}} or {{XRReferenceSpaceType/"local-floor"}} and the distance between the spaces' [=native origin=]'s is greater than a reasonable distance determined by the user agent, return <code>true</code>.
   1. Let |document| be |space|'s [=relevant global object=]'s [=associated document=].
-  1. If |document| is [=hidden=] return <code>true</code>.
   1. Return <code>false</code>.
 
 </div>