am b7cfc618: am 28fb09e0: cherry pick Change-Id: I183ff47e59617b2c17a92b876ca8c8bcc9b45262 docs: add document for the compatibility library

* commit 'b7cfc6181be090cc93d304a96e035f5a754085ae':
  cherry pick Change-Id: I183ff47e59617b2c17a92b876ca8c8bcc9b45262 docs: add document for the compatibility library