Make 'where' lazy.

sdk/lib/html/templates/html/dart2js/impl_SelectElement.darttemplate

Index: sdk/lib/html/templates/html/dart2js/impl_SelectElement.darttemplate
diff --git a/sdk/lib/html/templates/html/dart2js/impl_SelectElement.darttemplate b/sdk/lib/html/templates/html/dart2js/impl_SelectElement.darttemplate
index a22f7e826e64b223a2b65f4b40d56aa38cc8897f..31dee9da978ac2a3d0c07a8b9f3077c74d6c4304 100644
--- a/sdk/lib/html/templates/html/dart2js/impl_SelectElement.darttemplate
+++ b/sdk/lib/html/templates/html/dart2js/impl_SelectElement.darttemplate
@@ -10,13 +10,13 @@ $!MEMBERS
   // Override default options, since IE returns SelectElement itself and it
   // does not operate as a List.
   List<OptionElement> get options {
-    return this.elements.where((e) => e is OptionElement);
+    return this.elements.where((e) => e is OptionElement).toList();
   }
 
   List<OptionElement> get selectedOptions {
     // IE does not change the selected flag for single-selection items.
     if (this.multiple) {
-      return this.options.where((o) => o.selected);
+      return this.options.where((o) => o.selected).toList();
     } else {
       return [this.options[this.selectedIndex]];
     }