Fix hot reload test

pkg/front_end/test/src/incremental/hot_reload_e2e_test.dart

 // Copyright (c) 2017, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 /// Integration test that runs the incremental compiler, runs the compiled
 /// program, incrementally rebuild portions of the app, and triggers a hot
 /// reload on the running program.
 library front_end.incremental.hot_reload_e2e_test;
 
 import 'dart:async';
@@ skipping 30 matching lines @@
     compiler = await createIncrementalCompiler(
         'file:///a.dart', new HybridFileSystem(fs));
     await rebuild(compiler, outputUri); // this is a full compile.
   });
 
   tearDown(() async {
     outDir.deleteSync(recursive: true);
     lines = null;
   });
 
+  Future<int> computeVmPort() async {
+    var portLine = await lines[0];
+    expect(observatoryPortRegExp.hasMatch(portLine), isTrue);
+    var match = observatoryPortRegExp.firstMatch(portLine);
+    return int.parse(match.group(1));
+  }
+
+  /// Request vm to resume execution
+  Future resume() async {
+    var port = await computeVmPort();
+    var remoteVm = new RemoteVm(port);
+    await remoteVm.resume();
+  }
+
   /// Start the VM with the first version of the program compiled by the
   /// incremental compiler.
   startProgram(int reloadCount) async {
     var vmArgs = [
       '--enable-vm-service=0', // Note: use 0 to avoid port collisions.
-      '--platform=${platformFile.toFilePath()}',
+      '--pause_isolates_on_start',
+      '--kernel-binaries=${sdkRoot.toFilePath()}',
       outputUri.toFilePath()
     ];
     vmArgs.add('$reloadCount');
     var vm = await Process.start(Platform.executable, vmArgs);
     var splitter = new LineSplitter();
 
     /// The program prints at most 2 + reloadCount lines:
     ///  - a line displaying the observatory port
     ///  - a line before waiting for a reload
     ///  - a line after each hot-reload
     int i = 0;
     int expectedLines = 2 + reloadCount;
     var completers =
         new List.generate(expectedLines, (_) => new Completer<String>());
     lines = completers.map((c) => c.future).toList();
     vm.stdout.transform(UTF8.decoder).transform(splitter).listen((line) {
       expect(i, lessThan(expectedLines));
       completers[i++].complete(line);
     }, onDone: () {
       expect(i, expectedLines);
     });
 
     vm.stderr.transform(UTF8.decoder).transform(splitter).toList().then((err) {
       expect(err, isEmpty, reason: err.join('\n'));
     });
 
     programIsDone = vm.exitCode;
+    await resume();
   }
 
   /// Request a hot reload on the running program.
   Future hotReload() async {
-    var portLine = await lines[0];
-    expect(observatoryPortRegExp.hasMatch(portLine), isTrue);
-    var match = observatoryPortRegExp.firstMatch(portLine);
-    var port = int.parse(match.group(1));
-    var reloader = new VmReloader(port);
-    var reloadResult = await reloader.reload(outputUri);
+    var port = await computeVmPort();
+    var remoteVm = new RemoteVm(port);
+    var reloadResult = await remoteVm.reload(outputUri);
     expect(reloadResult['success'], isTrue);
-    await reloader.disconnect();
+    await remoteVm.disconnect();
   }
 
   test('initial program is valid', () async {
     await startProgram(0);
     await programIsDone;
-    expect(await lines.skip(1).first, "part1 part2");
+    expect(await lines[1], "part1 part2");
   });
 
   test('reload after leaf library modification', () async {
     await startProgram(1);
     expect(await lines[1], "part1 part2");
 
     writeFile(fs, 'b.dart', sourceB.replaceAll("part1", "part3"));
     await rebuild(compiler, outputUri);
     await hotReload();
     await programIsDone;
@@ skipping 37 matching lines @@
     writeFile(fs, 'a.dart', sourceA.replaceAll("part2", "part8"));
     await rebuild(compiler, outputUri);
     await hotReload();
     await programIsDone;
     expect(await lines[3], "part7 part8");
   });
 }
 
 var dartVm = Uri.base.resolve(Platform.resolvedExecutable);
 var sdkRoot = dartVm.resolve("patched_sdk/");
-var platformFile = sdkRoot.resolve('platform.dill');
 
 Future<IncrementalKernelGenerator> createIncrementalCompiler(
     String entry, FileSystem fs) {
   var entryUri = Uri.base.resolve(entry);
   var options = new CompilerOptions()
     ..sdkRoot = sdkRoot
     ..sdkSummary = sdkRoot.resolve('outline.dill')
     ..packagesFileUri = Uri.parse('file:///.packages')
     ..strongMode = false
     ..dartLibraries = loadDartLibraries()
@@ skipping 67 matching lines @@
 
 f() => "$line part2";
 ''';
 
 const sourceB = r'''
 get line => "part1";
 ''';
 
 RegExp observatoryPortRegExp =
     new RegExp("Observatory listening on http://127.0.0.1:\([0-9]*\)/");