Support Safari 6.1 stack traces with blank lines in pkg/stack_trace.

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:math' as math;
 
 import 'chain.dart';
@@ skipping 146 matching lines @@
   /// This will automatically decide between [parseSafari6_0] and
   /// [parseSafari6_1] based on the contents of [trace].
   factory Trace.parseSafari(String trace) {
     if (trace.contains(_safariTrace)) return new Trace.parseSafari6_1(trace);
     return new Trace.parseSafari6_0(trace);
   }
 
   /// Parses a string representation of a Safari 6.1+ stack trace.
   Trace.parseSafari6_1(String trace)
       : this(trace.trim().split("\n")
+          .where((line) => line.isNotEmpty)
           .map((line) => new Frame.parseSafari6_1(line)));
 
   /// Parses a string representation of a Safari 6.0 stack trace.
   ///
   /// Safari 6.0 stack traces look just like Firefox traces, except that they
   /// sometimes (e.g. in isolates) have a "[native code]" frame. We just ignore
   /// this frame to make the stack format more consistent between browsers.
   /// Prior to Safari 6.0, stack traces can't be retrieved.
   Trace.parseSafari6_0(String trace)
       : this(trace.trim().split("\n")
@@ skipping 63 matching lines @@
     // Figure out the longest path so we know how much to pad.
     var longest = frames.map((frame) => frame.location.length)
         .fold(0, math.max);
 
     // Print out the stack trace nicely formatted.
     return frames.map((frame) {
       return '${padRight(frame.location, longest)}  ${frame.member}\n';
     }).join();
   }
 }