All strong mode cleaning of dart2js.

tests/compiler/dart2js/mock_compiler.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 mock_compiler;
 
 import 'dart:async';
 import 'dart:collection';
 
 import 'package:compiler/compiler_new.dart' as api;
@@ skipping 135 matching lines @@
       startResolution();
       // We need to make sure the Object class is resolved. When registering a
       // dynamic invocation the ArgumentTypesRegistry eventually iterates over
       // the interfaces of the Object class which would be 'null' if the class
       // wasn't resolved.
       ClassElement objectClass = resolution.commonElements.objectClass;
       objectClass.ensureResolved(resolution);
     }).then((_) => uri);
   }
 
-  Future run(Uri uri, [String mainSource = ""]) {
+  Future<bool> run(Uri uri, [String mainSource = ""]) {
     return init(mainSource).then((Uri mainUri) {
       return super.run(uri == null ? mainUri : uri);
     }).then((result) {
       if (expectedErrors != null &&
           expectedErrors != diagnosticCollector.errors.length) {
         throw "unexpected error during compilation "
             "${diagnosticCollector.errors}";
       } else if (expectedWarnings != null &&
           expectedWarnings != diagnosticCollector.warnings.length) {
         throw "unexpected warnings during compilation "
@@ skipping 116 matching lines @@
   }
 
   /// Create a new [MockCompiler] and apply it asynchronously to [f].
   static Future create(f(MockCompiler compiler)) {
     MockCompiler compiler = new MockCompiler.internal();
     return compiler.init().then((_) => f(compiler));
   }
 }
 
 class MockResolvedUriTranslator implements ResolvedUriTranslator {
-  static final _emptySet = new Set();
+  static final dynamic _emptySet = new Set();
 
   Uri translate(LibraryElement importingLibrary, Uri resolvedUri,
           Spannable spannable) =>
       resolvedUri;
   Set<Uri> get disallowedLibraryUris => _emptySet;
   bool get mockableLibraryUsed => false;
   Map<String, Uri> get sdkLibraries => const <String, Uri>{};
 }
 
 class CollectingTreeElements extends TreeElementMapping {
@@ skipping 90 matching lines @@
       trustTypeAnnotations: trustTypeAnnotations,
       enableTypeAssertions: enableTypeAssertions,
       enableUserAssertions: enableUserAssertions,
       expectedErrors: expectedErrors,
       expectedWarnings: expectedWarnings,
       outputProvider: outputProvider);
   compiler.registerSource(uri, code);
   compiler.diagnosticHandler = createHandler(compiler, code);
   return compiler;
 }