Mojo: Add static factory functions to MessagePipe.

mojo/system/message_pipe.cc

Index: mojo/system/message_pipe.cc
diff --git a/mojo/system/message_pipe.cc b/mojo/system/message_pipe.cc
index efb8c6711b0b218384445fd02f511dcb0525513d..15b886b4568ab40c267670e82a0bd545f6313d7f 100644
--- a/mojo/system/message_pipe.cc
+++ b/mojo/system/message_pipe.cc
@@ -21,11 +21,21 @@ MessagePipe::MessagePipe(scoped_ptr<MessagePipeEndpoint> endpoint0,
   endpoints_[1].reset(endpoint1.release());
 }
 
-MessagePipe::MessagePipe() {
+MessagePipe::MessagePipe(LocalLocal) {
   endpoints_[0].reset(new LocalMessagePipeEndpoint());
   endpoints_[1].reset(new LocalMessagePipeEndpoint());
 }
 
+MessagePipe::MessagePipe(LocalProxy) {
+  endpoints_[0].reset(new LocalMessagePipeEndpoint());
+  endpoints_[1].reset(new ProxyMessagePipeEndpoint());
+}
+
+MessagePipe::MessagePipe(ProxyLocal) {
+  endpoints_[0].reset(new ProxyMessagePipeEndpoint());
+  endpoints_[1].reset(new LocalMessagePipeEndpoint());
+}
+
 // static
 unsigned MessagePipe::GetPeerPort(unsigned port) {
   DCHECK(port == 0 || port == 1);