Roll Observatory packages and add a roll script

stack_trace/lib/src/vm_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 vm_trace;
-
-import 'frame.dart';
-import 'utils.dart';
-
-/// An implementation of [StackTrace] that emulates the behavior of the VM's
-/// implementation.
-///
-/// In particular, when [toString] is called, this returns a string in the VM's
-/// stack trace format.
-class VMTrace implements StackTrace {
-  /// The stack frames that comprise this stack trace.
-  final List<Frame> frames;
-
-  VMTrace(this.frames);
-
-  String toString() {
-    var i = 1;
-    return frames.map((frame) {
-      var number = padRight("#${i++}", 8);
-      var member = frame.member
-          .replaceAllMapped(new RegExp(r"[^.]+\.<async>"),
-              (match) => "${match[1]}.<${match[1]}_async_body>")
-          .replaceAll("<fn>", "<anonymous closure>");
-      var line = frame.line == null ? 0 : frame.line;
-      var column = frame.column == null ? 0 : frame.column;
-      return "$number$member (${frame.uri}:$line:$column)\n";
-    }).join();
-  }
-}