Merge pull request #11221 from huchengtw-moz/video/Bug_898993_thumbnail_...

...size_is_not_compitable_to_hdpi

Bug 898993 - the creation of thumbnail size is not compatible to hdpi de...(cherry picked from commit 49b1f68b0e2152557bb7c2defb2a5f9d7a0648c6)

Conflicts:
	apps/video/js/video.js