Bug 985037 - Update a11y visiblity management in light of lockscreen changes.

We should not be setting aria-hidden on #windows anymore, instead it should be on individual apps.
Bug 985037 - Part 2, fix lockScreenWindow visibility state
[GAIA BUG886754] - Add highlighting to Contact Search results
Merge pull request #18783 from michalbe/Bug886754

Bug 886754 - Add highlighting to Contact Search results
Bug 999171 - Implement a progress indicator to show progress when the viewfinder has not loaded
Merge pull request #18518 from alivedise/bugzilla/985037_master/lockscreen-window-visibility

Bugzilla/985037 master/lockscreen window visibility, r=timdream
Merge pull request #18798 from wilsonpage/999171

Bug 999171 - Implement a progress indicator to show progress when the