Modify scanner and parser to be standalone packages.

pkg/dart_parser/lib/src/error_kind.dart

Index: pkg/dart_parser/lib/src/error_kind.dart
diff --git a/pkg/dart_parser/lib/src/error_kind.dart b/pkg/dart_parser/lib/src/error_kind.dart
new file mode 100644
index 0000000000000000000000000000000000000000..f5cd1b94d36791ad0a5a003e1afcf460dd7faaef
--- /dev/null
+++ b/pkg/dart_parser/lib/src/error_kind.dart
@@ -0,0 +1,31 @@
+// Copyright (c) 2016, 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 parser.error_kind;
+
+enum ErrorKind {
+  EMPTY_NAMED_PARAMETER_LIST,
+  EMPTY_OPTIONAL_PARAMETER_LIST,
+  EXPECTED_BODY,
+  EXPECTED_HEX_DIGIT,
+  EXPECTED_OPEN_PARENS,
+  EXPECTED_STRING,
+  EXTRANEOUS_MODIFIER,
+  EXTRANEOUS_MODIFIER_REPLACE,
+  INVALID_AWAIT_FOR,
+  INVALID_INPUT_CHARACTER,
+  INVALID_SYNC_MODIFIER,
+  INVALID_VOID,
+  MALFORMED_STRING_LITERAL,
+  MISSING_EXPONENT,
+  POSITIONAL_PARAMETER_WITH_EQUALS,
+  REQUIRED_PARAMETER_WITH_DEFAULT,
+  UNMATCHED_TOKEN,
+  UNSUPPORTED_PREFIX_PLUS,
+  UNTERMINATED_COMMENT,
+  UNTERMINATED_STRING,
+  UNTERMINATED_TOKEN,
+
+  UNSPECIFIED,
+}