Merge the dart:uri library into dart:core and update the Uri class

sdk/lib/_internal/compiler/implementation/compiler.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.
 
 part of dart2js;
 
 /**
  * If true, print a warning for each method that was resolved, but not
  * compiled.
  */
@@ skipping 723 matching lines @@
 
     initializeSpecialClasses();
 
     functionClass.ensureResolved(this);
     functionApplyMethod =
         functionClass.lookupLocalMember(const SourceString('apply'));
     jsInvocationMirrorClass.ensureResolved(this);
     invokeOnMethod = jsInvocationMirrorClass.lookupLocalMember(INVOKE_ON);
 
     if (preserveComments) {
-      var uri = new Uri.fromComponents(scheme: 'dart', path: 'mirrors');
+      var uri = new Uri(scheme: 'dart', path: 'mirrors');
       LibraryElement libraryElement =
           libraryLoader.loadLibrary(uri, null, uri);
       documentClass = libraryElement.find(const SourceString('Comment'));
     }
   }
 
   void importHelperLibrary(LibraryElement library) {
     if (jsHelperLibrary != null) {
       libraryLoader.importLibrary(library, jsHelperLibrary, null);
     }
@@ skipping 572 matching lines @@
 
   void close() {}
 
   toString() => name;
 
   /// Convenience method for getting an [api.CompilerOutputProvider].
   static NullSink outputProvider(String name, String extension) {
     return new NullSink('$name.$extension');
   }
 }