Merge pull request #20157 from julienw/1021844-sms-firefox

Bug 1021844 - [Messages] Can't load the application in Firefox r=schung
Merge pull request #20346 from mnjul/bug_1023448_lockscreen_notifications_color_overlay_brightness

Bug 1023448 - [VsD Refresh] Lockscreen Visual Refresh > Notifications background colour picker looks too light
Merge pull request #20345 from mnjul/bug_1023534_lockscreen_pin_camera_icon_low

Bug 1023534 - [VsD Refresh] Lockscreen Visual Refresh > Pin code screen > Camera icon position
Merge pull request #20338 from acperez/bug-1020152

Bug 1020152 - Generate pre_installed_collections.json in build time. r=yurenju