Add "PRIVATE" to the enum names of some private Pepper networking APIs:

ppapi/api/private/ppb_tcp_socket_private.idl

Index: ppapi/api/private/ppb_tcp_socket_private.idl
diff --git a/ppapi/api/private/ppb_tcp_socket_private.idl b/ppapi/api/private/ppb_tcp_socket_private.idl
index 5c5d54af41e0526d017040a67150978c9e1dd608..b9913bccfe84412260af3bdb21cf9bac4280e793 100644
--- a/ppapi/api/private/ppb_tcp_socket_private.idl
+++ b/ppapi/api/private/ppb_tcp_socket_private.idl
@@ -16,12 +16,12 @@ label Chrome {
 [assert_size(4)]
 enum PP_TCPSocketOption_Private {
   // Special value used for testing. Guaranteed to fail SetOption().
-  PP_TCPSOCKETOPTION_INVALID = 0,
+  PP_TCPSOCKETOPTION_PRIVATE_INVALID = 0,
 
   // Disable coalescing of small writes to make TCP segments, and instead
   // deliver data immediately. For SSL sockets, this option must be set before
   // SSLHandshake() is called. Value type is PP_VARTYPE_BOOL.
-  PP_TCPSOCKETOPTION_NO_DELAY = 1
+  PP_TCPSOCKETOPTION_PRIVATE_NO_DELAY = 1
 };
 
 /**