Report usage of deferred-components to analytics. (#159307)

Towards https://github.com/flutter/flutter/issues/159212.

/cc @jtmcdole

---------

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

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

@@ -310,6 +310,14 @@ class AssembleCommand extends FlutterCommand {
         "Try re-running 'flutter build ios' or the appropriate build command."
       );
     }
+    if (deferredTargets.isNotEmpty) {
+      // Record to analytics that DeferredComponents is being used.
+      globals.analytics.send(Event.flutterBuildInfo(
+        label: 'assemble-deferred-components',
+        buildType: 'android',
+        settings: deferredTargets.map((Target t) => t.name).join(','),
+      ));
+    }
     if (_flutterProject.manifest.deferredComponents != null
         && decodedDefines.contains('validate-deferred-components=true')
         && deferredTargets.isNotEmpty

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

@@ -143,6 +143,13 @@ class BuildAppBundleCommand extends BuildSubCommand {
     // Do all setup verification that doesn't involve loading units. Checks that
     // require generated loading units are done after gen_snapshot in assemble.
     final List<DeferredComponent>? deferredComponents = FlutterProject.current().manifest.deferredComponents;
+    if (deferredComponents != null && boolArg('deferred-components')) {
+      // Record to analytics that DeferredComponents is being used.
+      globals.analytics.send(Event.flutterBuildInfo(
+        label: 'build-appbundle-deferred-components',
+        buildType: 'android',
+      ));
+    }
     if (deferredComponents != null && boolArg('deferred-components') && boolArg('validate-deferred-components') && !boolArg('debug')) {
       final DeferredComponentsPrebuildValidator validator = DeferredComponentsPrebuildValidator(
         project.directory,

packages/flutter_tools/test/commands.shard/hermetic/assemble_test.dart

@@ -94,6 +94,35 @@ void main() {
     FeatureFlags: () => TestFeatureFlags(isMacOSEnabled: true),
   });
 
+  testUsingContext('flutter assemble sends assemble-deferred-components', () async {
+    final AssembleCommand command = AssembleCommand(
+      buildSystem: TestBuildSystem.all(BuildResult(success: true)),
+    );
+    final CommandRunner<void> commandRunner = createTestCommandRunner(command);
+    await commandRunner.run(<String>[
+      'assemble',
+      '-o Output',
+      '-dTargetPlatform=android',
+      '-dBuildMode=release',
+      'android_aot_deferred_components_bundle_release_android-arm64',
+    ]);
+    expect(
+      fakeAnalytics.sentEvents,
+      contains(
+        Event.flutterBuildInfo(
+          label: 'assemble-deferred-components',
+          buildType: 'android',
+          settings: 'android_aot_deferred_components_bundle_release_android-arm64',
+        ),
+      ),
+    );
+  }, overrides: <Type, Generator>{
+    Analytics: () => fakeAnalytics,
+    Cache: () => Cache.test(processManager: FakeProcessManager.any()),
+    FileSystem: () => MemoryFileSystem.test(),
+    ProcessManager: () => FakeProcessManager.any(),
+  });
+
   testUsingContext('flutter assemble sends usage values correctly with platform', () async {
     final AssembleCommand command = AssembleCommand(
         buildSystem: TestBuildSystem.all(BuildResult(success: true)));

packages/flutter_tools/test/commands.shard/permeable/build_appbundle_test.dart

@@ -148,6 +148,49 @@ void main() {
       Analytics: () => fakeAnalytics,
       ProcessInfo: () => processInfo,
     });
+
+    testUsingContext('use of the deferred components feature sends a build info event indicating so', () async {
+      final String projectPath = await createProject(
+        tempDir,
+        arguments: <String>[
+          '--empty',
+          '--no-pub',
+          '--template=app',
+        ],
+      );
+
+      // Add deferred manifest.
+      final File pubspec = globals.localFileSystem
+        .directory(projectPath)
+        .childFile('pubspec.yaml');
+      final String modifiedContents = pubspec
+        .readAsStringSync()
+        .replaceAll('flutter:', 'flutter:\n  deferred-components:');
+      pubspec.writeAsStringSync(modifiedContents);
+      printOnFailure(pubspec.readAsStringSync());
+
+      final Directory oldCwd = globals.localFileSystem.currentDirectory;
+      try {
+        globals.localFileSystem.currentDirectory = globals.localFileSystem.directory(projectPath);
+        await runBuildAppBundleCommand(projectPath);
+      } finally {
+        globals.localFileSystem.currentDirectory = oldCwd;
+      }
+
+      expect(
+        fakeAnalytics.sentEvents,
+        contains(
+          Event.flutterBuildInfo(
+            label: 'build-appbundle-deferred-components',
+            buildType: 'android',
+          ),
+        ),
+      );
+    }, overrides: <Type, Generator>{
+      AndroidBuilder: () => FakeAndroidBuilder(),
+      Analytics: () => fakeAnalytics,
+      ProcessInfo: () => processInfo,
+    });
   });
 
   group('Gradle', () {