Reorganize dartdoc to new package layout.

pkg/dartdoc/lib/mirrors.dart

 // Copyright (c) 2012, 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('mirrors');
 
 #import('dart:io');
 #import('dart:uri');
-#import('dart2js_mirror.dart');
+
+// TODO(rnystrom): Use "package:" URL (#4968).
+#import('src/mirrors/dart2js_mirror.dart');
 
 /**
  * [Compilation] encapsulates the compilation of a program.
  */
 class Compilation {
   /**
    * Creates a new compilation which has [script] as its entry point.
    */
   factory Compilation(Path script,
                       Path libraryRoot,
@@ skipping 439 matching lines @@
   /**
    * Returns the URI where the source originated.
    */
   Uri get uri;
 
   /**
    * Returns the text of this source.
    */
   String get text;
 }