Fix String.fromCharCodes to work with iterables.

runtime/lib/string_patch.dart

Index: runtime/lib/string_patch.dart
diff --git a/runtime/lib/string_patch.dart b/runtime/lib/string_patch.dart
index 6a9cf5497e5da5d3f3140c2b89f0cc9030ba0bf4..48035d415ecbceb940536f35a81de46bab821fd4 100644
--- a/runtime/lib/string_patch.dart
+++ b/runtime/lib/string_patch.dart
@@ -3,7 +3,7 @@
 // BSD-style license that can be found in the LICENSE file.
 
 patch class String {
-  /* patch */ factory String.fromCharCodes(List<int> charCodes) {
+  /* patch */ factory String.fromCharCodes(Iterable<int> charCodes) {
     return _StringBase.createFromCharCodes(charCodes);
   }
 }