sdk files reorganization to make dart2js a proper package

pkg/compiler/samples/darttags/darttags.dart

 // Copyright (c) 2013, 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.
 
 // Usage: Add the following to your .gclient file (found in the parent
 // of the "dart" in a gclient checkout of the Dart repositor).
 //
 // hooks = [
 //   {
 //     "pattern": ".",
@@ skipping 14 matching lines @@
 //
 //      (setq tags-table-list
 //           '("DART_LOCATION/dart"))
 //
 // Where DART_LOCATION is the gclient directory where you found .gclient.
 
 import 'dart:io';
 
 import 'dart:mirrors';
 
-import 'package:_internal/libraries.dart'
+import 'package:sdk_library_metadata/libraries.dart'
     show LIBRARIES, LibraryInfo;
 
 import 'package:compiler/src/mirrors/analyze.dart'
     show analyze;
 import 'package:compiler/src/mirrors/dart2js_mirrors.dart'
     show BackDoor;
 import 'package:compiler/src/mirrors/mirrors_util.dart' show nameOf;
 
 import 'package:compiler/src/filenames.dart';
 import 'package:compiler/src/io/source_file.dart';
@@ skipping 140 matching lines @@
 
     return new Definition(byte_offset, line_number, tag_definition_text);
   }
 
   void writeOn(StringBuffer buffer, String tagname) {
     buffer.write(
         '${tag_definition_text}\x7f${tagname}'
         '\x01${line_number},${byte_offset}\n');
   }
 }