Fix unused-parameter warnings in preparation for enabling them

gfe-relnote: n/a, compilation-only change
PiperOrigin-RevId: 253884032
Change-Id: Ib3af2f7ce5779e0fcf965ec9a9c054dac027087c
diff --git a/spdy/core/priority_write_scheduler.h b/spdy/core/priority_write_scheduler.h
index 067153b..20c9c13 100644
--- a/spdy/core/priority_write_scheduler.h
+++ b/spdy/core/priority_write_scheduler.h
@@ -134,7 +134,7 @@
   }
 
   std::vector<StreamIdType> GetStreamChildren(
-      StreamIdType stream_id) const override {
+      StreamIdType /*stream_id*/) const override {
     return std::vector<StreamIdType>();
   }