Bug 1037942 - Normalize alt in overwrite alternative layouts
Bug 1024333 - [v1.4][UX]Cannot turn off recent app page by tapping screen when "No recent app" is display

* Check if the cardsView is empty and should be closed or not in the onStartEvent event handler.
* Add test for closing empty cardsview by touchstart.
Bug 1008187 - [Camera] Update to use <gaia-header>
Merge pull request #21427 from begeeben/1024333_no_recent_app

Bug 1024333 - [v1.4][UX]Cannot turn off recent app page by tapping screen when "No recent app" is display, r=alive
Merge pull request #21654 from timdream/keyboard-alt-sublayout

Bug 1037942 - Normalize alt in overwrite alternative layouts, r=rudyl
Bug 971554 - [System2] Instantiable SoundManager
Merge pull request #19865 from wilsonpage/1008187

Bug 1008187 - [Camera] Update to use <gaia-header>
Merge pull request #18007 from huchengtw-moz/system2/Bug_971554-reland-3

Bug 971554 - [System2] Instantiable SoundManager, r=alive
Bug 1038024 - [Camera] Update camera to use gaia-icons v0.2.0
Merge pull request #21660 from wilsonpage/1038024

Bug 1038024 - [Camera] Update camera to use gaia-icons v0.2.0
Bug 1021505 - Modify Pinyin keybaord to new UX