TIF: call tune() in HardwareSession

Background: The underlying passthrough TV input expects tune() command
to show video on the screen and call notifyVideoAvailable().

Bug: 18551619
Change-Id: I257db321c09d621e6bd3c0e69bfe0abfca5742a9
diff --git a/media/java/android/media/tv/TvInputService.java b/media/java/android/media/tv/TvInputService.java
index 93cca2f..b19a1fb 100644
--- a/media/java/android/media/tv/TvInputService.java
+++ b/media/java/android/media/tv/TvInputService.java
@@ -1210,6 +1210,7 @@
                 }
                 mServiceHandler.obtainMessage(ServiceHandler.DO_NOTIFY_SESSION_CREATED, args)
                         .sendToTarget();
+                session.tune(TvContract.buildChannelUriForPassthroughInput(getHardwareInputId()));
             }
 
             @Override