Second round of cleanups for new optional parameter semantics.

tests/compiler/dart2js/mock_compiler.dart

 // Copyright (c) 2012, 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:uri");
 
 #import("../../../lib/compiler/implementation/elements/elements.dart");
 #import("../../../lib/compiler/implementation/leg.dart");
@@ skipping 56 matching lines @@
   class Null {}
   class Dynamic_ {}
   bool identical(Object a, Object b) {}''';
 
 class MockCompiler extends Compiler {
   List<WarningMessage> warnings;
   List<WarningMessage> errors;
   final Map<String, SourceFile> sourceFiles;
   Node parsedTree;
 
-  MockCompiler([String coreSource = DEFAULT_CORELIB,
-                String helperSource = DEFAULT_HELPERLIB,
-                String interceptorsSource = DEFAULT_INTERCEPTORSLIB,
-                bool enableTypeAssertions = false,
-                bool enableMinification = false])
+  MockCompiler({String coreSource: DEFAULT_CORELIB,
+                String helperSource: DEFAULT_HELPERLIB,
+                String interceptorsSource: DEFAULT_INTERCEPTORSLIB,
+                bool enableTypeAssertions: false,
+                bool enableMinification: false})
       : warnings = [], errors = [],
         sourceFiles = new Map<String, SourceFile>(),
         super(enableTypeAssertions: enableTypeAssertions,
               enableMinification: enableMinification) {
     coreLibrary = createLibrary("core", coreSource);
     // We need to set the assert method to avoid calls with a 'null'
     // target being interpreted as a call to assert.
     jsHelperLibrary = createLibrary("helper", helperSource);
     assertMethod = jsHelperLibrary.find(buildSourceString('assert'));
     interceptorsLibrary = createLibrary("interceptors", interceptorsSource);
@@ skipping 130 matching lines @@
     });
   }
 }
 
 LibraryElement mockLibrary(Compiler compiler, String source) {
   Uri uri = new Uri.fromComponents(scheme: "source");
   var library = new LibraryElement(new Script(uri, new MockFile(source)));
   importLibrary(library, compiler.coreLibrary, compiler);
   return library;
 }