Add a new command, run, to execute the runIde Gradle task (#7780)

tool/plugin/lib/plugin.dart

@@ -27,6 +27,7 @@ Future<int> main(List<String> args) async {
   runner.addCommand(DeployCommand(runner));
   runner.addCommand(GenerateCommand(runner));
   runner.addCommand(VerifyCommand(runner));
+  runner.addCommand(RunIdeCommand(runner));
 
   try {
     return await runner.run(args) ?? 0;
@@ -588,6 +589,42 @@ class GenerateCommand extends ProductCommand {
   }
 }
 
+/// Run the IDE using the gradle task "runIde"
+class RunIdeCommand extends ProductCommand {
+  @override
+  final BuildCommandRunner runner;
+
+  RunIdeCommand(this.runner) : super('run');
+
+  @override
+  String get description => 'Run the IDE plugin';
+
+  @override
+  Future<int> doit() async {
+    final javaHome = Platform.environment['JAVA_HOME'];
+    if (javaHome == null) {
+      log('JAVA_HOME environment variable not set - this is needed by Gradle.');
+      return 1;
+    }
+    log('JAVA_HOME=$javaHome');
+
+    // TODO(jwren) The IDE run is determined currently by the isUnitTestTarget
+    //  in the product-matrix.json, while useful, a new field should be added
+    //  into the product-matrix.json instead of re-using this field,
+    //  Or, the run IDE should be passed via the command line (I don't like this
+    //  as much.)
+    final spec = specs.firstWhere((s) => s.isUnitTestTarget);
+    return await _runIde(spec);
+  }
+
+  Future<int> _runIde(BuildSpec spec) async {
+    // run './gradlew runIde'
+    return await applyEdits(spec, () async {
+      return await runner.runGradleCommand(['runIde'], spec, '1', 'false');
+    });
+  }
+}
+
 abstract class ProductCommand extends Command<int> {
   @override
   final String name;