Update dart2js unit tests to dart_parser and dart_scanner.

tests/compiler/dart2js/parser_helper.dart

 // Copyright (c) 2016, 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.
 
 library parser_helper;
 
-import "package:expect/expect.dart";
+import 'package:expect/expect.dart';
 
-import "package:compiler/src/elements/elements.dart";
+import 'package:compiler/src/elements/elements.dart';
 import 'package:compiler/src/id_generator.dart';
-import "package:compiler/src/tree/tree.dart";
-import "package:compiler/src/parser/element_listener.dart";
-import "package:compiler/src/parser/node_listener.dart";
-import "package:compiler/src/parser/parser.dart";
-import "package:compiler/src/parser/partial_parser.dart";
-import "package:compiler/src/scanner/string_scanner.dart";
-import "package:compiler/src/tokens/token.dart";
-import "package:compiler/src/tokens/token_constants.dart";
-import "package:compiler/src/io/source_file.dart";
-import "package:compiler/src/util/util.dart";
+import 'package:compiler/src/tree/tree.dart';
+import 'package:compiler/src/parser/element_listener.dart';
+import 'package:compiler/src/parser/node_listener.dart';
+import 'package:compiler/src/parser/partial_elements.dart';
+import 'package:dart_parser/dart_parser.dart' hide parse;
+import 'package:dart_scanner/dart_scanner.dart' hide scan;
+import 'package:compiler/src/io/source_file.dart';
+import 'package:compiler/src/util/util.dart';
 
-import "package:compiler/src/elements/modelx.dart"
+import 'package:compiler/src/elements/modelx.dart'
     show CompilationUnitElementX, ElementX, LibraryElementX;
 
-import "package:compiler/src/compiler.dart";
+import 'package:compiler/src/compiler.dart';
 import 'package:compiler/src/options.dart';
-import "package:compiler/src/diagnostics/source_span.dart";
-import "package:compiler/src/diagnostics/spannable.dart";
-import "package:compiler/src/diagnostics/diagnostic_listener.dart";
-import "package:compiler/src/diagnostics/messages.dart";
-import "package:compiler/src/script.dart";
+import 'package:compiler/src/diagnostics/source_span.dart';
+import 'package:compiler/src/diagnostics/spannable.dart';
+import 'package:compiler/src/diagnostics/diagnostic_listener.dart';
+import 'package:compiler/src/diagnostics/messages.dart';
+import 'package:compiler/src/script.dart';
 
-import "options_helper.dart";
+import 'options_helper.dart';
 
-export "package:compiler/src/diagnostics/diagnostic_listener.dart";
-export 'package:compiler/src/parser/listener.dart';
+export 'package:dart_parser/dart_parser.dart' hide parse;
+export 'package:dart_scanner/dart_scanner.dart' hide scan;
+export 'package:compiler/src/diagnostics/diagnostic_listener.dart';
 export 'package:compiler/src/parser/node_listener.dart';
-export 'package:compiler/src/parser/parser.dart';
-export 'package:compiler/src/parser/partial_parser.dart';
 export 'package:compiler/src/parser/partial_elements.dart';
-export "package:compiler/src/tokens/token.dart";
-export "package:compiler/src/tokens/token_constants.dart";
+export 'package:dart_scanner/src/token_constants.dart';
 
 class LoggerCanceler extends DiagnosticReporter {
   DiagnosticOptions get options => const MockDiagnosticOptions();
 
   void log(message) {
     print(message);
   }
 
   void internalError(node, String message) {
     log(message);
   }
 
   SourceSpan spanFromSpannable(node) {
     throw 'unsupported operation';
   }
 
+  SourceSpan spanFromToken(token) => null;
+
   void reportError(DiagnosticMessage message,
       [List<DiagnosticMessage> infos = const <DiagnosticMessage>[]]) {
     log(message);
     infos.forEach(log);
   }
 
   void reportWarning(DiagnosticMessage message,
       [List<DiagnosticMessage> infos = const <DiagnosticMessage>[]]) {
     log(message);
     infos.forEach(log);
@@ skipping 16 matching lines @@
   DiagnosticMessage createMessage(Spannable spannable, MessageKind messageKind,
       [Map arguments = const {}]) {
     return new DiagnosticMessage(null, spannable,
         new Message(MessageTemplate.TEMPLATES[messageKind], arguments, false));
   }
 
   @override
   bool get hasReportedError => false;
 }
 
-Token scan(String text) => new StringScanner.fromString(text).tokenize();
+Token scan(String text) => new StringScanner(text).tokenize();
 
 Node parseBodyCode(String text, Function parseMethod,
     {DiagnosticReporter reporter}) {
   Token tokens = scan(text);
   if (reporter == null) reporter = new LoggerCanceler();
   Uri uri = new Uri(scheme: "source");
   Script script = new Script(uri, uri, new MockFile(text));
   LibraryElement library = new LibraryElementX(script);
   NodeListener listener = new NodeListener(
       new ScannerOptions(canUseNative: true),
@@ skipping 46 matching lines @@
       new IdGenerator());
   PartialParser parser = new PartialParser(listener);
   reporter.withCurrentElement(unit, () => parser.parseUnit(tokens));
   return unit.localMembers;
 }
 
 NodeList fullParseUnit(String source, {DiagnosticReporter reporter}) {
   return parseBodyCode(source, (parser, tokens) => parser.parseUnit(tokens),
       reporter: reporter);
 }