[flutter_tool] Change the startup message for the "flutter daemon" command (#160444)

There have been some reports of the Flutter daemon not starting up
properly (for ex. https://github.com/flutter/flutter/issues/143625), but
it turns out that when starting successfully, it just prints "Starting
device daemon..." and then nothing more. This is confusing and can lead
users to think other issues are because the daemon hasn't started
properly.

There's not a great hook to print that this "finished" starting up
(because it does async polling in the background), so I just updated the
message of the text and moved it to after the creation of the daemon.

Fixes https://github.com/flutter/flutter/issues/143625

## Pre-launch Checklist

- [x] I read the [Contributor Guide] and followed the process outlined
there for submitting PRs.
- [x] I read the [Tree Hygiene] wiki page, which explains my
responsibilities.
- [x] I read and followed the [Flutter Style Guide], including [Features
we expect every widget to implement].
- [x] I signed the [CLA].
- [x] I listed at least one issue that this PR fixes in the description
above.
- [x] I updated/added relevant documentation (doc comments with `///`).
- [x] I added new tests to check the change I am making, or this PR is
[test-exempt].
- [N/A] I followed the [breaking change policy] and added [Data Driven
Fixes] where supported.
- [x] All existing and new tests are passing.

If you need help, consider asking for advice on the #hackers-new channel
on [Discord].

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---------

Co-authored-by: Andrew Kolos <andrewrkolos@gmail.com>

packages/flutter_tools/lib/src/commands/daemon.dart

@@ -86,7 +86,6 @@ class DaemonCommand extends FlutterCommand {
       ).run();
       return FlutterCommandResult.success();
     }
-    globals.printStatus('Starting device daemon...');
     final Daemon daemon = Daemon(
       DaemonConnection(
         daemonStreams: DaemonStreams.fromStdio(globals.stdio, logger: globals.logger),
@@ -94,6 +93,7 @@ class DaemonCommand extends FlutterCommand {
       ),
       notifyingLogger: asLogger<NotifyingLogger>(globals.logger),
     );
+    globals.printStatus('Device daemon started.');
     final int code = await daemon.onExit;
     if (code != 0) {
       throwToolExit('Daemon exited with non-zero exit code: $code', exitCode: code);

packages/flutter_tools/test/integration.shard/daemon_mode_test.dart

@@ -27,6 +27,42 @@ void main() {
     daemonProcess.kill();
   });
 
+  testWithoutContext('startup events', () async {
+    final BasicProject project = BasicProject();
+    await project.setUpIn(tempDir);
+
+    const ProcessManager processManager = LocalProcessManager();
+    daemonProcess = await processManager.start(
+      <String>[flutterBin, ...getLocalEngineArguments(), '--show-test-device', 'daemon'],
+      workingDirectory: tempDir.path,
+    );
+
+    final StreamController<String> stdout = StreamController<String>.broadcast();
+    transformToLines(daemonProcess.stdout).listen((String line) => stdout.add(line));
+    final Stream<Map<String, Object?>> stream =
+        stdout.stream
+            .map<Map<String, Object?>?>(parseFlutterResponse)
+            .where((Map<String, Object?>? value) => value != null)
+            .cast<Map<String, Object?>>();
+
+    final [
+      Map<String, Object?> connectedEvent,
+      Map<String, Object?> logMessage,
+    ] = await Future.wait(<Future<Map<String, Object?>>>[
+      stream.firstWhere((Map<String, Object?> e) => e['event'] == 'daemon.connected'),
+      stream.firstWhere((Map<String, Object?> e) => e['event'] == 'daemon.logMessage'),
+    ]);
+
+    // Check the connected message has a version.
+    final Map<String, Object?> connectedParams = connectedEvent['params']! as Map<String, Object?>;
+    expect(connectedParams['version'], isNotNull);
+
+    // Check we got the startup message.
+    final Map<String, Object?> logParams = logMessage['params']! as Map<String, Object?>;
+    expect(logParams['level'], 'status');
+    expect(logParams['message'], 'Device daemon started.');
+  });
+
   testWithoutContext('device.getDevices', () async {
     final BasicProject project = BasicProject();
     await project.setUpIn(tempDir);