如何创建可以传递给GoogleApiClient构建器的YouTube API类?
mGoogleApiClient = new GoogleApiClient.Builder(getActivity())
.addApi(Plus.API)
.addApi(null)//<========================================INSERT YOUTUBE API HERE
.addScope(Plus.SCOPE_PLUS_LOGIN)
.addScope(Plus.SCOPE_PLUS_PROFILE)
.addScope(CustomScopes.VIEW_YOUTUBE)
.addConnectionCallbacks(this)
.addOnConnectionFailedListener(this)
.build();