Rename mappedBy to map.

pkg/path/lib/path.dart

 // Copyright (c) 2012, 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.
 
 /// A comprehensive, cross-platform path manipulation library.
 library path;
 
 import 'dart:io' as io;
 
 /// An internal builder for the current OS so we can provide a straight
@@ skipping 161 matching lines @@
 
     var numArgs;
     for (numArgs = args.length; numArgs >= 1; numArgs--) {
       if (args[numArgs - 1] != null) break;
     }
 
     // Show the arguments.
     var message = new StringBuffer();
     message.add("$method(");
     message.add(args.take(numArgs)
-        .mappedBy((arg) => arg == null ? "null" : '"$arg"')
+        .map((arg) => arg == null ? "null" : '"$arg"')
         .join(", "));
     message.add("): part ${i - 1} was null, but part $i was not.");
     throw new ArgumentError(message.toString());
   }
 }
 
 /// An instantiable class for manipulating paths. Unlike the top-level
 /// functions, this lets you explicitly select what platform the paths will use.
 class Builder {
   /// Creates a new path builder for the given style and root directory.
@@ skipping 499 matching lines @@
     // If there is no dot, or it's the first character, like '.bashrc', it
     // doesn't count.
     if (lastDot <= 0) return [file, ''];
 
     return [file.substring(0, lastDot), file.substring(lastDot)];
   }
 
   _ParsedPath clone() => new _ParsedPath(
       style, root, new List.from(parts), new List.from(separators));
 }