CCodec: fix handling buffers in extra slots

Bug: 192638680
Test: cts/media/device-small
Change-Id: I93deb01900c8f134524f6e38905b7ab2f278206d
diff --git a/media/codec2/sfplugin/CCodecBuffers.cpp b/media/codec2/sfplugin/CCodecBuffers.cpp
index ba44074..cfa89cf 100644
--- a/media/codec2/sfplugin/CCodecBuffers.cpp
+++ b/media/codec2/sfplugin/CCodecBuffers.cpp
@@ -129,6 +129,7 @@
     if (!copy->copy(c2buffer)) {
         return nullptr;
     }
+    copy->meta()->extend(buffer->meta());
     return copy;
 }