Add various filter events callbacks after filter starting in the Filter
default impl

Note: these events are only for testing purpose. This would make sure
that CTS could cover more of the Filter events codes.

Test: atest android.media.tv.tuner.cts
Bug: 181152149
Change-Id: I8b4318a384af75646b61060f849353602ecefc03
diff --git a/tv/tuner/1.1/default/Demux.cpp b/tv/tuner/1.1/default/Demux.cpp
index f4e4a91..db25c2e 100644
--- a/tv/tuner/1.1/default/Demux.cpp
+++ b/tv/tuner/1.1/default/Demux.cpp
@@ -340,6 +340,10 @@
 }
 
 void Demux::frontendInputThreadLoop() {
+    if (!mFrontendInputThreadRunning) {
+        return;
+    }
+
     std::lock_guard<std::mutex> lock(mFrontendInputThreadLock);
     if (!mDvrPlayback) {
         ALOGW("[Demux] No software Frontend input configured. Ending Frontend thread loop.");