Proxies are an implementation detail, so make them private to hide
them from the public API.
Also, move the proxy classes out of its interface scope; classes
declared inside Java interfaces are always public and cannot be
declared otherwise. Use the lowercase "proxy" class prefix to
avoid name clashes with exported Go interfaces and structs.
Change-Id: Iae6a53ed4885b7899f2fa770b73c135f54ffb263
Reviewed-on: https://go-review.googlesource.com/21370
Reviewed-by: David Crawshaw <crawshaw@golang.org>
e1840f9c11