Move parser and token related libraries into their own subfolder.

pkg/compiler/lib/src/scanner/array_based_scanner.dart

 // Copyright (c) 2011, 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 dart2js.scanner.array_based;
 
 import '../io/source_file.dart' show
     SourceFile;
-import '../util/characters.dart' show
-    $LF,
-    $STX;
-import '../util/util.dart' show
-    Link;
-
-import 'keyword.dart' show
+import '../tokens/keyword.dart' show
     Keyword;
-import 'scanner.dart' show
-    AbstractScanner;
-import 'token.dart' show
+import '../tokens/token.dart' show
     BeginGroupToken,
     COMMENT_INFO,
     ErrorToken,
     EOF_INFO,
     LT_TOKEN,
     KeywordToken,
     OPEN_CURLY_BRACKET_TOKEN,
     PrecedenceInfo,
     STRING_INTERPOLATION_TOKEN,
     SymbolToken,
     Token;
+import '../util/characters.dart' show
+    $LF,
+    $STX;
+import '../util/util.dart' show
+    Link;
+
+import 'scanner.dart' show
+    AbstractScanner;
 
 abstract class ArrayBasedScanner extends AbstractScanner {
   ArrayBasedScanner(SourceFile file, bool includeComments)
       : super(file, includeComments);
 
   /**
    * The stack of open groups, e.g [: { ... ( .. :]
    * Each BeginGroupToken has a pointer to the token where the group
    * ends. This field is set when scanning the end group token.
    */
@@ skipping 195 matching lines @@
    * something which cannot possibly be part of a type parameter/argument
    * list, like the '=' in the above example.
    */
   void discardOpenLt() {
     while (!groupingStack.isEmpty
         && identical(groupingStack.head.kind, LT_TOKEN)) {
       groupingStack = groupingStack.tail;
     }
   }
 }