Remove deprecated mappedBy.

Committed: https://code.google.com/p/dart/source/detail?r=18575
Reverted: http://code.google.com/p/dart/source/detail?r=18576

Review URL: https://codereview.chromium.org//12212213

git-svn-id: https://dart.googlecode.com/svn/branches/bleeding_edge/dart@18579 260f80e4-7a28-3924-810f-c04153c831b5

runtime/lib/byte_array.dart

@@ -233,10 +233,6 @@ abstract class _ByteArrayBase {
     return IterableMixinWorkaround.mapList(this, f);
   }
 
-  List mappedBy(f(int element)) {
-    return IterableMixinWorkaround.mappedByList(this, f);
-  }
-
   String join([String separator]) {
     return IterableMixinWorkaround.join(this, separator);
   }