Introduce the ability to dump the wbxml from EAS responses.

Similar to CurlLogger that dumps the base64 represention of
the EAS request, WbxmlResponseLogger will dump the base64
representation of responses from the server so that we can
easily view the XML payload. Unit tests included.

Change-Id: I96e2c2d508ac27002125ee83d307ff7cd75400c7
(cherry picked from commit 17403f2cc87358e7b768cb982921d28694a7932d)
3 files changed