Merge branch 'master' into update_nnbd

Changed the order of the setters for mediaRecorder in MediaRecorderBu…

…ilder.java to make it more readable. (flutter#3181)

[google_maps_flutter_web] Show one InfoWindow at a time. (flutter#3224)

[in_app_purchase] Bump version (flutter#3227)

Follow-up for flutter#3220 (forgot to bump in that PR).

[google_maps_flutter] Overhaul lifecycle management in GoogleMapsPlug…

…in (flutter#3213)

GoogleMapController is now uniformly driven by implementing DefaultLifecycleObserver. That observer is registered to a lifecycle passed via the new LifecycleProvider interface, which has 3 implementations:
1. For v2 plugin registration, GoogleMapsPlugin implements the interface and holds the lifecycle in a field, which is itself controlled by ActivityAware methods.
2. For v1 plugin registration, if the activity implements LifecycleOwner, it's lifecycle is used directly.
3. For v1 plugin registration, if the activity does not implement LifecycleOwner, a proxy lifecycle is created via ActivityLifecycleCallbacks.

[camera] Added documentation about video not working correctly on And…

…roid emulators (flutter#3180)

* Added information of video not working correctly on Android emulators to `README.md`.

* Changed up the text and added a link

* Version fix

* Update packages/camera/README.md

Co-authored-by: Maurits van Beusekom <[email protected]>

* Improve grammar as suggested

Co-authored-by: Maurice Parrish <[email protected]>

Co-authored-by: Maurits van Beusekom <[email protected]>
Co-authored-by: Maurice Parrish <[email protected]>

[video_player] Fix pubspec

[video_player_web] Allow to publish

[url_launcher] Fix dependencies

[video_player] Fix changelog