Revert "Merge pull request #14745 from huchengtw-moz/video/Bug_915039_add_cancel_button"

This reverts commit a523c1ee4130a7883981924f8e68fb94be02428a, reversing
changes made to 83688a4f70774f1f96f4621f781024fcc925bce9.
Merge pull request #15053 from huchengtw-moz/video/Bug_915039_revert

Revert "Merge pull request #14745 from huchengtw-moz/video/Bug_915039_ad...