EDK: Add Core::DuplicateHandleWithReducedRights().

mojo/edk/system/core.h

Index: mojo/edk/system/core.h
diff --git a/mojo/edk/system/core.h b/mojo/edk/system/core.h
index a97010f3aeca3e3110ff3fade881019e975b98a6..b4cfbda02ef695c8782bd5852b28bedc8c24b202 100644
--- a/mojo/edk/system/core.h
+++ b/mojo/edk/system/core.h
@@ -117,6 +117,10 @@ class Core {
   // "mojo/public/c/system/handle.h":
   MojoResult Close(MojoHandle handle);
   MojoResult GetRights(MojoHandle handle, UserPointer<MojoHandleRights> rights);
+  MojoResult DuplicateHandleWithReducedRights(
+      MojoHandle handle,
+      MojoHandleRights rights_to_remove,
+      UserPointer<MojoHandle> new_handle);
 
   // These methods correspond to the API functions defined in
   // "mojo/public/c/system/wait.h":