Clean-up of getCompilationUnit.

lib/compiler/implementation/js/printer.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.
 
 class Printer implements NodeVisitor {
   final bool shouldCompressOutput = false;
   leg.Compiler compiler;
   var positionElement;
   leg.CodeBuffer outBuffer;
   int indentLevel = 0;
@@ skipping 619 matching lines @@
     // a reserved word.
     return true;
   }
 
   visitAccess(PropertyAccess access) {
     visitNestedExpression(access.receiver, CALL,
                           newInForInit: inForInit,
                           newAtStatementBegin: atStatementBegin);
     Node selector = access.selector;
     if (selector is LiteralString) {
-      String fieldWithQuotes = (selector as LiteralString).value;
+      LiteralString selectorString = selector;
+      String fieldWithQuotes = selectorString.value;
       if (isValidJavaScriptId(fieldWithQuotes)) {
         if (isDigit(lastCharCode)) out(" ");
         out(".");
         out(fieldWithQuotes.substring(1, fieldWithQuotes.length - 1));
         return;
       }
     }
     out("[");
     visitNestedExpression(selector, EXPRESSION,
                           newInForInit: false, newAtStatementBegin: false);
@@ skipping 63 matching lines @@
         out(",");
         spaceOut();
       }
       visitProperty(properties[i]);
     }
     out("}");
   }
 
   visitProperty(Property node) {
     if (node.name is LiteralString) {
-      String name = (node.name as LiteralString).value;
+      LiteralString nameString = node.name;
+      String name = nameString.value;
       if (isValidJavaScriptId(name)) {
         out(name.substring(1, name.length - 1));
       } else {
         out(name);
       }
     } else {
       assert(node.name is LiteralNumber);
-      out((node.name as LiteralNumber).value);
+      LiteralNumber nameNumber = node.name;
+      out(nameNumber.value);
     }
     out(":");
     spaceOut();
     visitNestedExpression(node.value, ASSIGNMENT,
                           newInForInit: false, newAtStatementBegin: false);
   }
 
   visitRegExpLiteral(RegExpLiteral node) {
     out(node.pattern);
   }
@@ skipping 70 matching lines @@
 }
 
 
 leg.CodeBuffer prettyPrint(Node node,
                            leg.Compiler compiler,
                            Dynamic positionElement) {
   Printer printer = new Printer(compiler, positionElement);
   printer.visit(node);
   return printer.outBuffer;
 }