MediaCodec: add background mode

Bug: 183751395
Test: manual
Change-Id: If60634c62d44bb828ba309ce376daeddd5d6332f
diff --git a/media/codec2/sfplugin/C2OMXNode.cpp b/media/codec2/sfplugin/C2OMXNode.cpp
index f66dc11..c049187 100644
--- a/media/codec2/sfplugin/C2OMXNode.cpp
+++ b/media/codec2/sfplugin/C2OMXNode.cpp
@@ -90,6 +90,10 @@
         }
     }
 
+    void setPriority(int priority) {
+        androidSetThreadPriority(getTid(), priority);
+    }
+
 protected:
     bool threadLoop() override {
         constexpr nsecs_t kIntervalNs = nsecs_t(10) * 1000 * 1000;  // 10ms
@@ -529,4 +533,8 @@
     return *mDataspace.lock();
 }
 
+void C2OMXNode::setPriority(int priority) {
+    mQueueThread->setPriority(priority);
+}
+
 }  // namespace android