Address additional analysis issues in the observatory codebase.

runtime/observatory/tests/service/async_star_single_step_into_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.
 // VMOptions=--error_on_bad_type --error_on_bad_override  --verbose_debug --async_debugger
 
 import 'dart:developer';
-import 'package:observatory/models.dart' as M;
-import 'package:observatory/service_io.dart';
-import 'package:unittest/unittest.dart';
+import 'dart:io';
+
 import 'service_test_common.dart';
 import 'test_helper.dart';
 
-const LINE_A = 21;
-const LINE_B = 22;
-const LINE_C = 26;
-const LINE_D = 29;
-const LINE_E = 35;
-const LINE_F = 36;
-
 foobar() async* {
   yield 1; // LINE_A.
   yield 2; // LINE_B.
 }
 
 helper() async {
   print('helper'); // LINE_C.
   await for (var i in foobar()) {
     debugger();
     print('loop'); // LINE_D.
   }
 }
 
 testMain() {
   debugger();
   print('mmmmm'); // LINE_E.
   helper(); // LINE_F.
   print('z');
 }
 
+final ScriptLineParser lineParser = new ScriptLineParser(Platform.script);
+
 var tests = [
   hasStoppedAtBreakpoint,
-  stoppedAtLine(LINE_E),
+  stoppedAtLine(lineParser.lineFor('LINE_E')),
   stepOver, // print.
   hasStoppedAtBreakpoint,
-  stoppedAtLine(LINE_F),
+  stoppedAtLine(lineParser.lineFor('LINE_F')),
   stepInto,
   hasStoppedAtBreakpoint,
-  stoppedAtLine(LINE_C),
+  stoppedAtLine(lineParser.lineFor('LINE_C')),
   stepOver, // print.
   hasStoppedAtBreakpoint,
   stepInto,
   hasStoppedAtBreakpoint,
-  stoppedAtLine(LINE_A),
+  stoppedAtLine(lineParser.lineFor('LINE_A')),
   // Resume here to exit the generator function.
   // TODO(johnmccutchan): Implement support for step-out of async functions.
   resumeIsolate,
   hasStoppedAtBreakpoint,
-  stoppedAtLine(LINE_D),
+  stoppedAtLine(lineParser.lineFor('LINE_D')),
   stepOver, // print.
   hasStoppedAtBreakpoint,
   stepInto,
   hasStoppedAtBreakpoint,
-  stoppedAtLine(LINE_B),
+  stoppedAtLine(lineParser.lineFor('LINE_B')),
   resumeIsolate,
 ];
 
 main(args) =>
     runIsolateTestsSynchronous(args, tests, testeeConcurrent: testMain);