Add mount sources for a MountNode (inode)

native_client_sdk/src/libraries/nacl_mounts/mount_node_dir.h

Index: native_client_sdk/src/libraries/nacl_mounts/mount_node_dir.h
===================================================================
--- native_client_sdk/src/libraries/nacl_mounts/mount_node_dir.h	(revision 131457)
+++ native_client_sdk/src/libraries/nacl_mounts/mount_node_dir.h	(working copy)
@@ -32,7 +32,8 @@
   // Adds a finds or adds a directory entry as an INO, updating the refcount
   virtual int AddChild(const std::string& name, MountNode *node);
   virtual int RemoveChild(const std::string& name);
-  virtual MountNode*  FindChild(const std::string& name);
+  virtual MountNode* FindChild(const std::string& name);
+  virtual int ChildCount();
 
 
 protected:
@@ -42,7 +43,8 @@
 private:
   struct dirent* cache_;
   MountNodeMap_t map_;
-  friend class Mount;
+
+  friend class MountMem;
 };
 
 #endif  // LIBRARIES_NACL_MOUNTS_MOUNT_NODE_DIR_H_