Change Tuner Frontend Callback to align with the aidl callback interface

Test: make libtunerservice
Bug: 172079283
Change-Id: I788d333448ae61d2008187e832276b19921299b8
diff --git a/services/tuner/TunerService.h b/services/tuner/TunerService.h
index 26591ab..8de6187 100644
--- a/services/tuner/TunerService.h
+++ b/services/tuner/TunerService.h
@@ -80,6 +80,7 @@
     TunerService();
     virtual ~TunerService();
 
+    // TODO: create a map between resource id and handles.
     static int getResourceIdFromHandle(int resourceHandle) {
         return (resourceHandle & 0x00ff0000) >> 16;
     }