Deprecate old Q mode API

Changed functions not to be pure virtual, so that downstream
implementations can be removed.

Bug: b/260859962

Change-Id: I4c1c225a5523307101af1d5102b775e3a9d25a1f
diff --git a/av1/qmode_rc/ratectrl_qmode_interface.h b/av1/qmode_rc/ratectrl_qmode_interface.h
index 558485c..a7fff4a 100644
--- a/av1/qmode_rc/ratectrl_qmode_interface.h
+++ b/av1/qmode_rc/ratectrl_qmode_interface.h
@@ -322,15 +322,18 @@
   // ref_frame_table_snapshot_init; for subsequent GOPs, it should be the
   // final_snapshot returned on the previous call.
   //
-  // TODO(b/260859962): Remove these once the extension to use firstpass stats
-  // is done.
+  // TODO(b/260859962): Remove these once all callers and overrides are gone.
   virtual StatusOr<GopEncodeInfo> GetGopEncodeInfo(
-      const GopStruct &gop_struct, const TplGopStats &tpl_gop_stats,
-      const std::vector<LookaheadStats> &lookahead_stats,
-      const RefFrameTable &ref_frame_table_snapshot_init) = 0;
-
+      const GopStruct &gop_struct AOM_UNUSED,
+      const TplGopStats &tpl_gop_stats AOM_UNUSED,
+      const std::vector<LookaheadStats> &lookahead_stats AOM_UNUSED,
+      const RefFrameTable &ref_frame_table_snapshot AOM_UNUSED) {
+    return Status{ AOM_CODEC_UNSUP_FEATURE, "Deprecated" };
+  }
   virtual StatusOr<GopEncodeInfo> GetTplPassGopEncodeInfo(
-      const GopStruct &gop_struct) = 0;
+      const GopStruct &gop_struct AOM_UNUSED) {
+    return Status{ AOM_CODEC_UNSUP_FEATURE, "Deprecated" };
+  }
 
   // Extensions to the API to pass in the first pass info. There should be stats
   // for all frames starting from the first frame of the GOP and continuing to