Added 'dynamic' keyword, so that 'Dynamic' can be deprecated.

lib/compiler/implementation/resolver.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.
 
 abstract class TreeElements {
   Element operator[](Node node);
   Selector getSelector(Send send);
   DartType getType(TypeAnnotation annotation);
   bool isParameterChecked(Element element);
 }
@@ skipping 837 matching lines @@
     Send send = node.typeName.asSend();
     return resolveTypeNameInternal(scope, typeName, send);
   }
 
   Element resolveTypeNameInternal(Scope scope, Identifier typeName, Send send) {
     if (send !== null) {
       typeName = send.selector;
     }
     if (typeName.source.stringValue === 'void') {
       return compiler.types.voidType.element;
-    } else if (typeName.source.stringValue === 'Dynamic') {
+    } else if (
+        // TODO(aprelev@gmail.com): Remove deprecated Dynamic keyword support.
+        typeName.source.stringValue === 'Dynamic'
+        || typeName.source.stringValue === 'dynamic') {
       return compiler.dynamicClass;
     } else if (send !== null) {
       Element e = scope.lookup(send.receiver.asIdentifier().source);
       if (e !== null && e.kind === ElementKind.PREFIX) {
         // The receiver is a prefix. Lookup in the imported members.
         PrefixElement prefix = e;
         return prefix.lookupLocalMember(typeName.source);
       } else if (e !== null && e.kind === ElementKind.CLASS) {
         // The receiver is the class part of a named constructor.
         return e;
@@ skipping 2011 matching lines @@
 
   Element localLookup(SourceString name) => library.find(name);
   Element lookup(SourceString name) => localLookup(name);
   Element lexicalLookup(SourceString name) => localLookup(name);
 
   Element add(Element newElement) {
     throw "Cannot add an element in the top scope";
   }
   String toString() => '$element';
 }