MediaCodec: add background mode

Bug: 183751395
Test: manual
Change-Id: If60634c62d44bb828ba309ce376daeddd5d6332f
diff --git a/media/codec2/sfplugin/C2OMXNode.h b/media/codec2/sfplugin/C2OMXNode.h
index 9c04969..6669318 100644
--- a/media/codec2/sfplugin/C2OMXNode.h
+++ b/media/codec2/sfplugin/C2OMXNode.h
@@ -98,6 +98,11 @@
      */
     android_dataspace getDataspace();
 
+    /**
+     * Sets priority of the queue thread.
+     */
+    void setPriority(int priority);
+
 private:
     std::weak_ptr<Codec2Client::Component> mComp;
     sp<IOMXBufferSource> mBufferSource;