Revert "Improve time to development by initializing frontend_server...

Revert "Improve time to development by initializing frontend_server concurrently with platform build (#45236)" (#45422)

packages/flutter_tools/lib/src/compile.dart

@@ -468,6 +468,7 @@ abstract class ResidentCompiler {
     List<String> dartDefines,
   }) = DefaultResidentCompiler;
 
+
   /// If invoked for the first time, it compiles Dart script identified by
   /// [mainPath], [invalidatedFiles] list is ignored.
   /// On successive runs [invalidatedFiles] indicates which files need to be

packages/flutter_tools/lib/src/devfs.dart

@@ -487,9 +487,6 @@ class DevFS {
     if (fullRestart) {
       generator.reset();
     }
-    // On a full restart, or on an initial compile for the attach based workflow,
-    // this will produce a full dill. Subsequent invocations will produce incremental
-    // dill files that depend on the invalidated files.
     printTrace('Compiling dart to kernel with ${invalidatedFiles.length} updated files');
     final CompilerOutput compilerOutput = await generator.recompile(
       mainPath,

packages/flutter_tools/lib/src/run_hot.dart

@@ -18,7 +18,6 @@ import 'base/platform.dart';
 import 'base/terminal.dart';
 import 'base/utils.dart';
 import 'build_info.dart';
-import 'bundle.dart';
 import 'compile.dart';
 import 'convert.dart';
 import 'devfs.dart';
@@ -263,31 +262,14 @@ class HotRunner extends ResidentRunner {
 
     firstBuildTime = DateTime.now();
 
-    final List<Future<bool>> startupTasks = <Future<bool>>[];
     for (FlutterDevice device in flutterDevices) {
-      // Here we initialize the frontend_server conccurently with the gradle
-      // build, reducing initialization time. This is safe because the first
-      // invocation of the frontend server produces a full dill file that
-      // the subsequent invocation in devfs will not overwrite.
-      if (device.generator != null) {
-        startupTasks.add(
-          device.generator.recompile(
-            mainPath,
-            <Uri>[],
-            outputPath: dillOutputPath ??
-              getDefaultApplicationKernelPath(trackWidgetCreation: device.trackWidgetCreation),
-            packagesFilePath : packagesFilePath,
-          ).then((CompilerOutput output) => output?.errorCount == 0)
-        );
-      }
-      startupTasks.add(device.runHot(
+      final int result = await device.runHot(
         hotRunner: this,
         route: route,
-      ).then((int result) => result == 0));
-    }
-    final List<bool> results = await Future.wait(startupTasks);
-    if (!results.every((bool passed) => passed)) {
-      return 1;
+      );
+      if (result != 0) {
+        return result;
+      }
     }
 
     return attach(

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

@@ -108,18 +108,13 @@ void main() {
   });
 
   test('hot reload doesn\'t reassemble if paused', () async {
-    final Future<void> setup = _flutter.run(withDebugger: true);
-    final Completer<void> sawTick1 = Completer<void>();
+    await _flutter.run(withDebugger: true);
     final Completer<void> sawTick2 = Completer<void>();
     final Completer<void> sawTick3 = Completer<void>();
     final Completer<void> sawDebuggerPausedMessage1 = Completer<void>();
     final Completer<void> sawDebuggerPausedMessage2 = Completer<void>();
     final StreamSubscription<String> subscription = _flutter.stdout.listen(
       (String line) {
-        if (line.contains('((((TICK 1))))')) {
-          expect(sawTick1.isCompleted, isFalse);
-          sawTick1.complete();
-        }
         if (line.contains('((((TICK 2))))')) {
           expect(sawTick2.isCompleted, isFalse);
           sawTick2.complete();
@@ -134,8 +129,6 @@ void main() {
         }
       },
     );
-    await setup;
-    await sawTick1.future;
     await _flutter.addBreakpoint(
       _project.buildBreakpointUri,
       _project.buildBreakpointLine,