Make stack frames without columns print correctly.

pkg/stack_trace/lib/src/frame.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 frame;
 
 
 import 'package:path/path.dart' as path;
 
 import 'trace.dart';
@@ skipping 60 matching lines @@
 
   /// Returns the name of the package this stack frame comes from, or `null` if
   /// this stack frame doesn't come from a `package:` URL.
   String get package {
     if (uri.scheme != 'package') return null;
     return uri.path.split('/').first;
   }
 
   /// A human-friendly description of the code location.
   String get location {
-    if (line == null || column == null) return library;
+    if (line == null) return library;
+    if (column == null) return '$library $line';
     return '$library $line:$column';
   }
 
   /// Returns a single frame of the current stack.
   ///
   /// By default, this will return the frame above the current method. If
   /// [level] is `0`, it will return the current method's frame; if [level] is
   /// higher than `1`, it will return higher frames.
   factory Frame.caller([int level=1]) {
     if (level < 0) {
@@ skipping 101 matching lines @@
 
     var line = match[2] == null ? null : int.parse(match[2]);
     var column = match[3] == null ? null : int.parse(match[3]);
     return new Frame(uri, line, column, match[4]);
   }
 
   Frame(this.uri, this.line, this.column, this.member);
 
   String toString() => '$location in $member';
 }