Update docs about command line flags (#2725)
diff --git a/CONTRIBUTING.md b/CONTRIBUTING.md
index 0664f85..e8290b2 100644
--- a/CONTRIBUTING.md
+++ b/CONTRIBUTING.md
@@ -77,23 +77,23 @@
Once you've got everything set up, you can run an example using your locally
built engine by switching to that example's directory, running `pub get` to make
sure its dependencies have been downloaded, and using `flutter run` with an
-explicit `--engine-src-path` pointing at the `engine/src` directory. Make sure you have
-a device connected over USB and debugging enabled on that device:
+explicit `--local-engine-src-path` pointing at the `engine/src` directory. Make
+sure you have a device connected over USB and debugging enabled on that device:
* `cd /path/to/flutter/examples/hello_world`
* `pub get`
- * `../../bin/flutter run --engine-src-path /path/to/engine/src`
+ * `../../bin/flutter run --local-engine-src-path /path/to/engine/src --local-engine=android_debug_unopt`
-If you put the `engine` and `flutter` directories side-by-side, you can use
-`--engine-debug` instead of the tedious `--engine-src-path /path/to/engine/src`,
-and the `flutter` tool will automatically determine the path.
+If you put the `engine` and `flutter` directories side-by-side, you can skip the
+tedious `--local-engine-src-path` option and the `flutter` tool will
+automatically determine the path.
You can also specify a particular Dart file to run if you want to run an example
that doesn't have a `lib/main.dart` file using the `-t` command-line option. For
example, to run the `tabs.dart` example in the `examples/widgets` directory on a
connected Android device, from that directory you would run:
- * `flutter run --engine-debug -t tabs.dart`
+ * `flutter run --local-engine=android_debug_unopt -t tabs.dart`
If you're going to be debugging crashes in the engine, make sure you add
`android:debuggable="true"` to the `<application>` element in the
