Revert "Add reduce to Collection."

runtime/lib/array.dart

Index: runtime/lib/array.dart
diff --git a/runtime/lib/array.dart b/runtime/lib/array.dart
index 15d3219910bbda047ca532167fd348aac57f197b..9980d5da6ff4edbf18a0b52a7de3afc0ead7cf5e 100644
--- a/runtime/lib/array.dart
+++ b/runtime/lib/array.dart
@@ -88,11 +88,6 @@ class ObjectArray<E> implements List<E> {
     return Collections.map(this, new GrowableObjectArray.withCapacity(length), f);
   }
 
-  Dynamic reduce(Dynamic initialValue,
-                 Dynamic combine(Dynamic previousValue, E element)) {
-    return Collections.reduce(this, initialValue, combine);
-  }
-
   Collection<E> filter(bool f(E element)) {
     return Collections.filter(this, new GrowableObjectArray<E>(), f);
   }
@@ -225,11 +220,6 @@ class ImmutableArray<E> implements List<E> {
     return Collections.map(this, new GrowableObjectArray.withCapacity(length), f);
   }
 
-  Dynamic reduce(Dynamic initialValue,
-                 Dynamic combine(Dynamic previousValue, E element)) {
-    return Collections.reduce(this, initialValue, combine);
-  }
-
   Collection<E> filter(bool f(E element)) {
     return Collections.filter(this, new GrowableObjectArray<E>(), f);
   }