Implement getRange (returning an Iterable).

tools/dom/templates/html/impl/impl_Node.darttemplate

Index: tools/dom/templates/html/impl/impl_Node.darttemplate
diff --git a/tools/dom/templates/html/impl/impl_Node.darttemplate b/tools/dom/templates/html/impl/impl_Node.darttemplate
index ac9990e488b3e128ffa7f46c75e1d7f501f5102e..68d8c48fdb3d50540e54dd1af821121b5c3638cb 100644
--- a/tools/dom/templates/html/impl/impl_Node.darttemplate
+++ b/tools/dom/templates/html/impl/impl_Node.darttemplate
@@ -177,14 +177,16 @@ $endif
     throw new UnsupportedError(
         "Cannot insertRange on immutable List.");
   }
+
+  Iterable<Node> getRange(int start, int end) {
+    throw new UnimplementedError("NodeList.getRange");
+  }
+
   List<Node> sublist(int start, [int end]) {
     if (end == null) end == length;
     return Lists.getRange(this, start, end, <Node>[]);
   }
 
-  List<Node> getRange(int start, int rangeLength) =>
-      sublist(start, start + rangeLength);
-
   String toString() {
     StringBuffer buffer = new StringBuffer('[');
     buffer.writeAll(this, ', ');