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

lib/compiler/implementation/resolver.dart

Index: lib/compiler/implementation/resolver.dart
diff --git a/lib/compiler/implementation/resolver.dart b/lib/compiler/implementation/resolver.dart
index ef8c2274e9123266caef50952b78fc5b8ae411e7..dae6d4f0db1d0674caf5756b7278a3d5955e9ac0 100644
--- a/lib/compiler/implementation/resolver.dart
+++ b/lib/compiler/implementation/resolver.dart
@@ -855,7 +855,10 @@ class TypeResolver {
     }
     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);