Hello gmlewis@google.com (cc: golang-codereviews@googlegroups.com), I'd like you to review this change to https://code.google.com/p/goprotobuf
LGTM
*** Submitted as https://code.google.com/p/goprotobuf/source/detail?r=988645649e33 *** goprotobuf: Add method to extending message to get list of messages extended. LGTM=gmlewis R=gmlewis CC=golang-codereviews https://codereview.appspot.com/159790043