Google Drive XBlock - Fake PR for review purposes, do not merge!

@martynjames Created this PR for the review. 

Btw for the future, it's easier to create this when the first commit is empty. Also, if we want to review a series of PRs at once instead of individual PRs, it would be easier to merge the individual PRs in a branch which isn't master, and then create a PR from that branch into master when it's ready -- this way we don't need "fake" PRs at all, they represent the actual review workflow.
Is there a way to accomplish width/height in a way so that it is not hardcoded in the xBlock? I'd be concerned if the xblock viewport changes, we'd end up with scrollbars in the outer container. Does the width/height come as part of the embed code from Google?