We used to be able to toggle observatory via a command line flag. But now, we enable or disable observatory based on the Flutter product mode.
This also allows us to fix an issue where the —non-interactive flags was being hijacked by the Dart initialization logic to enable or disable observatory. However this flag was orignally meant for the standalone runner to launch either to run tests or to run a full graphics enabled window on the desktop.
* Add config properties to specify snapshot blob file names.
This adds the ability of the shell to override the default
dart aot snapshot blob file names, and it wires up Android's
FlutterMain to recognize the properties in the app's manifest.
This will be used for flutter applications that build their
binary snapshots into files other than the default ones
that the engine uses.
