Revert "Merge pull request #20999 from KevinGrandon/land_bug_1027271"

This reverts commit c5ff624a02d947730e34085d1bacad5231e01850, reversing
changes made to a4a9be1879a026bcd6a4559e6f49151390a0a120.
Bug 1027271 - [Rocketbar] banner becomes transparent occasionally when transitioning to browser. r=etienne
Merge pull request #21036 from vingtetun/backout-bug1027271-reland

Backout bug1027271 reland