1643 suppress deprecation warning for BinaryMessages (cla: yes)

1644 [cloud_firestore] Add user agent submission to Firestore plugin (cla: yes)

1645 [webview_flutter] Move the method channel behind the platform interface (cla: yes)

1647 [cloud_firestore] Added source support (cla: yes, flutterfire)

1648 [connectivity]Adding missing type params. (cla: yes)

1649 [Device_info] Replace invokeMethod with invokeMapMethod and some refactoring around this change. (cla: yes)

1650 [cloud_firestore]bump up flutter version to 1.5 and use invokeMapMethod instead of invokeMethod (cla: yes, flutterfire)

1651 [firebase_admob]add missing type params for invokeMethod and bump min flutter version to 1.5.0… (cla: yes)