1694 [shared_preferences]Add missing template type parameter to invokeMethod calls. Bump minimum Flutter version to 1.5.0. Replace invokeMethod with invokeMapMethod wherever necessary. (cla: yes)

1695 [url_launcher] Add missing template type parameter to invokeMethod calls. Bump minimum Flutter version to 1.5.0. Replace invokeMethod with invokeMapMethod wherever necessary. (cla: yes)

1696 [video_player] Add missing template type parameter to invokeMethod calls. Bump minimum Flutter version to 1.5.0. Replace invokeMethod with invokeMapMethod wherever necessary. (cla: yes)

1697 [google_maps_flutter] Add support for styling google maps (cla: yes)

1698 [webview_flutter]Add missing template type parameter to invokeMethod calls. Bump minimum Flutter version to 1.5.0. Replace invokeMethod with invokeMapMethod wherever necessary. (cla: yes)