Merge pull request #17297 from etiennesegonzac/bug-982196-reflow-helper-upgrade

Bug 982196 - Upgrading the ReflowHelper to use the new devtools tooling.
Bug 971546 - [System2] Instantiable Screenshot
Bug 971577 - [System] Make visibility manager instantiable
Bug 961800 - Implement Child Window Factory

Conflicts:
	apps/system/js/app_transition_controller.js
	apps/system/js/app_window.js
	apps/system/js/app_window_manager.js
	apps/system/js/cards_view.js
	apps/system/style/window.css
Bug 971556 - [System2] Instantiable SourceView.
Bug 970028 - Nicer activity opener animation
Bug 974828 - [Settings][dsds] Outgoing data confirmation is wrong

- update test
- change the way about how we show confirm window
Bug 983507 - Make airplane mode icon appear via airplaneMode setting, not RIL status
Merge pull request #17215 from russnicoletti/bug982743

Bug 982743 - [B2G][Clock]Timer section's Resume button illuminates and doesn't resume timer countdown r=mcav
Merge pull request #17214 from qdot/983507-flight-mode-radio-off

Bug 983507 - Make airplane mode icon appear via airplaneMode setting, not RIL status
Bug 981887 - Update button design using current BB structure and "Plan B" design
Merge pull request #17202 from rnowm/981887

Bug 981887 - Update button design using current BB structure and "Plan B" design
Bug 981610 - Remove some CSS warnings on the keyboard app. r=janjongboom
Merge pull request #17334 from vingtetun/bug981610.keyboards

Bug 981610 - Remove some CSS warnings on the keyboard app. r=janjongboom
Bug 981610 - Remove some CSS warnings on shared/. r=arnau
Merge pull request #17337 from vingtetun/bug981610.shared

Bug 981610 - Remove some CSS warnings on shared/. r=arnau
Merge pull request #17223 from vingtetun/bug984151

Bug 984151 - Make the contacts image pull up effect smoother. r=arcturus
Reversed BB Switches for RTL
Bug 983760 - Dont show crash screen if tab is not currently active. r=daleharvey
Bug 929917 - UI Test app for Firefox Accounts DOM API