Integrated internal changes from Google

This includes all internal changes from around May 20 to now.
diff --git a/js/test.proto b/js/test.proto
index 6b9dc89..06eb79a 100644
--- a/js/test.proto
+++ b/js/test.proto
@@ -160,6 +160,7 @@
   optional string str = 1;
   optional Simple1 simple1 = 3;
   repeated Simple1 simple2 = 5;
+  optional bytes bytes_field = 6;
   optional string unused = 7;
   extensions 10 to max;
 }