Tuner HAL default implementation for Demux and Descrambler Interface.

Bug: 135709325
Test: Manual
Change-Id: I38a92abb761d2d39e8e6a495f2d93dee5f1c9d90
diff --git a/tv/tuner/1.0/default/Tuner.h b/tv/tuner/1.0/default/Tuner.h
index 1ca7671..12e9594 100644
--- a/tv/tuner/1.0/default/Tuner.h
+++ b/tv/tuner/1.0/default/Tuner.h
@@ -47,6 +47,9 @@
     vector<sp<Frontend>> mFrontends;
     // To maintain how many Frontends we have
     int mFrontendSize;
+    // The last used demux id. Initial value is -1.
+    // First used id will be 0.
+    int mLastUsedId = -1;
 };
 
 }  // namespace implementation