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

pkg/stack_trace/lib/src/trace.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.
 
 library trace;
 
 import 'dart:collection';
-import 'dart:uri';
 import 'dart:math' as math;
 
 import 'frame.dart';
 import 'lazy_trace.dart';
 
 final _patchRegExp = new RegExp(r"-patch$");
 
 /// A stack trace, comprised of a list of stack frames.
 class Trace implements StackTrace {
   /// The stack frames that comprise this stack trace.
@@ skipping 114 matching lines @@
   if (string.length >= length) return string;
 
   var result = new StringBuffer();
   result.write(string);
   for (var i = 0; i < length - string.length; i++) {
     result.write(' ');
   }
 
   return result.toString();
 }