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/Frontend.h b/tv/tuner/aidl/default/Frontend.h
index a98cc92..3c602cf 100644
--- a/tv/tuner/aidl/default/Frontend.h
+++ b/tv/tuner/aidl/default/Frontend.h
@@ -33,7 +33,7 @@
 
 class Frontend : public BnFrontend {
   public:
-    Frontend(FrontendType type, int32_t id, Tuner* tuner);
+    Frontend(FrontendType type, int32_t id, std::shared_ptr<Tuner> tuner);
 
     ::ndk::ScopedAStatus setCallback(
             const std::shared_ptr<IFrontendCallback>& in_callback) override;
@@ -59,7 +59,7 @@
     virtual ~Frontend();
     bool supportsSatellite();
     std::shared_ptr<IFrontendCallback> mCallback;
-    Tuner* mTuner;
+    std::shared_ptr<Tuner> mTuner;
     FrontendType mType = FrontendType::UNDEFINED;
     int32_t mId = 0;
     bool mIsLocked = false;