Add tests for handling closures in LocalInitializers

pkg/kernel/lib/transformations/argument_extraction_for_redirecting.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.
+
+library kernel.transformations.argument_extraction_for_redirecting;
+
+import '../ast.dart'
+    show
+        Program,
+        Constructor,
+        RedirectingInitializer,
+        Library,
+        LocalInitializer,
+        VariableDeclaration,
+        VariableGet,
+        Expression,
+        NamedExpression;
+import '../core_types.dart' show CoreTypes;
+import '../visitor.dart' show Transformer;
+
+Program transformProgram(CoreTypes coreTypes, Program program) {
+  new ArgumentExtractionForRedirecting().visitProgram(program);
+  return program;
+}
+
+void transformLibraries(CoreTypes coreTypes, List<Library> libraries) {
+  var transformer = new ArgumentExtractionForRedirecting();
+  for (var library in libraries) {
+    transformer.visitLibrary(library);
+  }
+}
+
+class ArgumentExtractionForRedirecting extends Transformer {
+  visitConstructor(Constructor node) {
+    if (node.initializers.length == 1 &&
+        node.initializers[0] is RedirectingInitializer) {
+      int index = 0;
+      RedirectingInitializer redirectingInitializer = node.initializers[0];
+      List<Expression> positionalArguments =
+          redirectingInitializer.arguments.positional;
+      List<NamedExpression> namedArguments =
+          redirectingInitializer.arguments.named;
+      for (int i = 0; i < positionalArguments.length; i++) {
+        Expression argument = positionalArguments[i];
+        VariableDeclaration extractedArgument =
+            new VariableDeclaration("extracted#$index", initializer: argument);
+        LocalInitializer initializer = new LocalInitializer(extractedArgument)
+          ..parent = node;
+        node.initializers.insert(index++, initializer);
+        positionalArguments[i] = new VariableGet(extractedArgument)
+          ..parent = redirectingInitializer.arguments;
+      }
+      for (int i = 0; i < namedArguments.length; i++) {
+        Expression argument = namedArguments[i].value;
+        VariableDeclaration extractedArgument =
+            new VariableDeclaration("extracted#$index", initializer: argument);
+        LocalInitializer initializer = new LocalInitializer(extractedArgument)
+          ..parent = node;
+        node.initializers.insert(index++, initializer);
+        namedArguments[i].value = new VariableGet(extractedArgument)
+          ..parent = redirectingInitializer.arguments;
+      }
+    }
+    return super.visitConstructor(node);
+  }
+}