Add init() to avoid crash when creating ref in constructor.

This reverts commit 50899fb2696d2bb98a4807a237e124f566293f57.

Bug: 195717690
Fix: 195717690
Test: atest VtsHalTvTunerTargetTest
Change-Id: Icae435f1166e6cf2e2f235979e3d1d37d182d517
diff --git a/tv/tuner/aidl/default/Dvr.cpp b/tv/tuner/aidl/default/Dvr.cpp
index 7c9c44c..9eadb8c 100644
--- a/tv/tuner/aidl/default/Dvr.cpp
+++ b/tv/tuner/aidl/default/Dvr.cpp
@@ -31,7 +31,8 @@
 
 #define WAIT_TIMEOUT 3000000000
 
-Dvr::Dvr(DvrType type, uint32_t bufferSize, const std::shared_ptr<IDvrCallback>& cb, Demux* demux) {
+Dvr::Dvr(DvrType type, uint32_t bufferSize, const std::shared_ptr<IDvrCallback>& cb,
+         std::shared_ptr<Demux> demux) {
     mType = type;
     mBufferSize = bufferSize;
     mCallback = cb;