Add thunks for MojoDuplicateHandle[WithReducedRights]().

mojo/public/platform/native/system_thunks.c

Index: mojo/public/platform/native/system_thunks.c
diff --git a/mojo/public/platform/native/system_thunks.c b/mojo/public/platform/native/system_thunks.c
index 9ed890fb53a0e6caff55a4a247d56a4bb13b71e2..6cff1cbaa3d5343148d33b0cf2a5feb8f47dfedc 100644
--- a/mojo/public/platform/native/system_thunks.c
+++ b/mojo/public/platform/native/system_thunks.c
@@ -25,6 +25,20 @@ MojoResult MojoGetRights(MojoHandle handle, MojoHandleRights* rights) {
   return g_thunks.GetRights(handle, rights);
 }
 
+MojoResult MojoDuplicateHandleWithReducedRights(
+    MojoHandle handle,
+    MojoHandleRights rights_to_remove,
+    MojoHandle* new_handle) {
+  assert(g_thunks.DuplicateHandleWithReducedRights);
+  return g_thunks.DuplicateHandleWithReducedRights(handle, rights_to_remove,
+                                                   new_handle);
+}
+
+MojoResult MojoDuplicateHandle(MojoHandle handle, MojoHandle* new_handle) {
+  assert(g_thunks.DuplicateHandle);
+  return g_thunks.DuplicateHandle(handle, new_handle);
+}
+
 MojoResult MojoWait(MojoHandle handle,
                     MojoHandleSignals signals,
                     MojoDeadline deadline,