Add Chain.foldFrames to 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 211 matching lines @@
     }));
   }
 
   /// Returns a new [Trace] based on [this] where multiple stack frames matching
   /// [predicate] are folded together. This means that whenever there are
   /// multiple frames in a row that match [predicate], only the last one is
   /// kept.
   ///
   /// This is useful for limiting the amount of library code that appears in a
   /// stack trace by only showing user code and code that's called by user code.
-  Trace foldFrames(bool predicate(frame)) {
+  Trace foldFrames(bool predicate(Frame frame)) {
     var newFrames = <Frame>[];
     for (var frame in frames.reversed) {
       if (!predicate(frame)) {
         newFrames.add(frame);
       } else if (newFrames.isEmpty || !predicate(newFrames.last)) {
         newFrames.add(new Frame(
             frame.uri, frame.line, frame.column, frame.member));
       }
     }
 
     return new Trace(newFrames.reversed);
   }
 
   /// Returns a human-readable string representation of [this].
   String toString() {
     // 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();
   }
 }