[mojo] Implement pipe fusion API

mojo/edk/system/node_controller.h

Index: mojo/edk/system/node_controller.h
diff --git a/mojo/edk/system/node_controller.h b/mojo/edk/system/node_controller.h
index c103e03e239918aa60334233279f22d5f70a6cd0..75d28926e09af39007215fde0d841b47906ae2dd 100644
--- a/mojo/edk/system/node_controller.h
+++ b/mojo/edk/system/node_controller.h
@@ -90,6 +90,9 @@ class NodeController : public ports::NodeDelegate,
   void MergePortIntoParent(const std::string& token,
                            const ports::PortRef& port);
 
+  // Merges two local ports together.
+  int MergeLocalPorts(const ports::PortRef& port0, const ports::PortRef& port1);
+
   // Creates a new shared buffer for use in the current process.
   scoped_refptr<PlatformSharedBuffer> CreateSharedBuffer(size_t num_bytes);