Fix direct uses of document and global

[zpao]

8f15eea introduced a couple uses. We need to fix them because

1. global isn't actually available (though we need to be careful about using window directly as well - 458836a)
2. document breaks server rendering - ReferenceError: document is not defined facebookarchive/react-page#28

[sophiebits]

Also we're trying to make rendering into iframes work, so document is probably usually/always the wrong thing to use?

[zpao]

84dea7e fixed some of this.

[petehunt]

+1 @spicyj

[zpao]

Closing this out - no need to keep the general issue around.