Tuner: Clean up frontend sharee resource before sharing another resource

Before sharing another resource in shareFrontendFromTuner method Clean
up old frontend sharee.

Test: cts-tradefed run commandAndExit cts -m CtsTvTestCases -t
android.media.tv.tuner.cts.TunerTest
Bug: 284386302

Change-Id: I606de9f4a95923183d0e2e94a8e73f9c0ed5df43

media/java/android/media/tv/tuner/Tuner.java

@@ -443,6 +443,12 @@ public class Tuner implements AutoCloseable  {
         acquireTRMSLock("shareFrontendFromTuner()");
         mFrontendLock.lock();
         try {
+            if (mFeOwnerTuner != null) {
+                // unregister self from the Frontend callback
+                mFeOwnerTuner.unregisterFrontendCallbackListener(this);
+                mFeOwnerTuner = null;
+                nativeUnshareFrontend();
+            }
             mTunerResourceManager.shareFrontend(mClientId, tuner.mClientId);
             mFeOwnerTuner = tuner;
             mFeOwnerTuner.registerFrontendCallbackListener(this);