4100 [webview_flutter] Suppress iOS 9 deprecation warnings (cla: yes, p: webview_flutter, platform-ios)

4108 Add Basic Junit Tests to some plugins (cla: yes, p: webview_flutter, p: google_sign_in, p: local_auth, p: video_player, p: shared_preferences, platform-android)

4137 [various] Prepare plugin repo for binding API improvements (cla: yes, waiting for tree to go green, p: battery, p: webview_flutter, p: camera, p: video_player, p: sensors, p: connectivity)

4147 Fix webview_flutter Android integration tests and add Espresso (cla: yes, waiting for tree to go green, p: webview_flutter, platform-android)