Optimize splitting lines with many rules.

lib/src/debug.dart

 // Copyright (c) 2014, 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.
 
 /// Internal debugging utilities.
 library dart_style.src.debug;
 
 import 'dart:math' as math;
 
 import 'chunk.dart';
@@ skipping 100 matching lines @@
       if (predicate) {
         row.add(callback());
       } else {
         row.add("");
       }
     }
 
     if (chunk.rule != null) {
       row.add(chunk.isHardSplit ? "" : chunk.rule.toString());
 
-      var outerRules = chunk.rule.outerRules.toSet().intersection(rules);
-      writeIf(outerRules.isNotEmpty, () => "-> ${outerRules.join(" ")}");
+      var constrainedRules =
+          chunk.rule.constrainedRules.toSet().intersection(rules);
+      writeIf(constrainedRules.isNotEmpty,
+          () => "-> ${constrainedRules.join(" ")}");
     } else {
       row.add("(no rule)");
 
       // Outer rules.
       row.add("");
     }
 
     writeIf(chunk.indent != null && chunk.indent != 0,
         () => "indent ${chunk.indent}");
 
@@ skipping 74 matching lines @@
 
       if (chunk.spaceWhenUnsplit) buffer.write(" ");
     }
   }
 
   buffer.write(chunks.last.text);
   log(buffer);
 }
 
 String _color(String ansiEscape) => useAnsiColors ? ansiEscape : "";