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

lib/compiler/implementation/scanner/keyword.dart

Index: lib/compiler/implementation/scanner/keyword.dart
diff --git a/lib/compiler/implementation/scanner/keyword.dart b/lib/compiler/implementation/scanner/keyword.dart
index b5b69194ec42e1f77f11cbb4c2460a794469c20b..be4e6520bcfb259ef854a548340edce98bd7269b 100644
--- a/lib/compiler/implementation/scanner/keyword.dart
+++ b/lib/compiler/implementation/scanner/keyword.dart
@@ -42,6 +42,7 @@ class Keyword implements SourceString {
       const Keyword("abstract", isBuiltIn: true),
       const Keyword("as", info: AS_INFO, isBuiltIn: true),
       const Keyword("assert", isBuiltIn: true),
+      const Keyword("dynamic", isBuiltIn: true),
       const Keyword("external", isBuiltIn: true),
       const Keyword("factory", isBuiltIn: true),
       const Keyword("get", isBuiltIn: true),
@@ -63,7 +64,8 @@ class Keyword implements SourceString {
       const Keyword("show", isPseudo: true),
       const Keyword("source", isPseudo: true) ];
 
-  static const DYNAMIC = const Keyword("Dynamic", isBuiltIn: true);
+  // TODO(aprelev@gmail.com): Remove deprecated Dynamic keyword support.
+  static const DYNAMIC_DEPRECATED = const Keyword("Dynamic", isBuiltIn: true);
 
   final String syntax;
   final bool isPseudo;