Fix for Issue 2399.

lib/dom/templates/immutable_list_mixin.darttemplate

Index: lib/dom/templates/immutable_list_mixin.darttemplate
diff --git a/lib/dom/templates/immutable_list_mixin.darttemplate b/lib/dom/templates/immutable_list_mixin.darttemplate
index befa0d71b7413662508dd1f5bf4893c0e2b686c3..d2e2c0adc0caac1a68c28eec7300232c4b43e93c 100644
--- a/lib/dom/templates/immutable_list_mixin.darttemplate
+++ b/lib/dom/templates/immutable_list_mixin.darttemplate
@@ -46,21 +46,30 @@
   int indexOf($E element, [int start = 0]) =>
       _Lists.indexOf(this, element, start, this.length);
 
-  int lastIndexOf($E element, [int start = 0]) =>
-      _Lists.lastIndexOf(this, element, start);
+  int lastIndexOf($E element, [int start]) {
+    if (start === null) start = length - 1;
+    return _Lists.lastIndexOf(this, element, start);
+  }
 
   $E last() => this[length - 1];
 
+  $E removeLast() {
+    throw new UnsupportedOperationException("Cannot removeLast on immutable List.");
+  }
+
   // FIXME: implement these.
   void setRange(int start, int rangeLength, List<$E> from, [int startFrom]) {
     throw new UnsupportedOperationException("Cannot setRange on immutable List.");
   }
+
   void removeRange(int start, int rangeLength) {
     throw new UnsupportedOperationException("Cannot removeRange on immutable List.");
   }
+
   void insertRange(int start, int rangeLength, [$E initialValue]) {
     throw new UnsupportedOperationException("Cannot insertRange on immutable List.");
   }
+
   List<$E> getRange(int start, int rangeLength) =>
       _Lists.getRange(this, start, rangeLength, <$E>[]);