Make sandboxContext extend LauncherApplication (4/n)

See
https://docs.google.com/drawings/d/1JHFi_nhmQt2xPT1N3FB_1mnaRK5TVqKZ9-fSl3EA7sU/edit?usp=sharing
and
https://docs.google.com/drawings/d/1bx4WURP4uHZGzZ1bWQgpw701jkTkVqlNfA02Yt-ZtSI/edit?usp=sharing&resourcekey=0-oySjsnaCsOSrNIPqqEa0gw
for design details.

We need to make SandboxContext extend LauncherApplication because we
want create MainThreadInitializedObjects in SandboxContext's
AppComponent scope. Since MainThreadInitiliazedObjects are closed in
SandboxContext's OnDestroy() , we need to replicate same thing using
dagger as well.

- DaggerSingletonObject is same as MainThreadInitializedObject but is
  used for fetching the dagger created singletons so that we can avoid
  major refactors for accessing singletons. This will be deleted soon.

- DaggerSingletonTracker to track dagger created singletons and call
  close() on those singleton objects created in SandboxContext scope.

- Annotate the singleton object SettingsChangeLogger constructor with @Inject and execute the statements in Main thread.
- Added createSandboxContextForTest(only for Test) to avoid creation of
  dagger component in test. As follow up, I will delete this method and
  introduce fakeDaggerComponents in test.

Bug: 361850561
Test: Manual
Flag: NONE Dagger Integration

Change-Id: I2d3762ea64e53baa4de190790568aec750b54201

src/com/android/launcher3/LauncherApplication.java

@@ -18,6 +18,7 @@ package com.android.launcher3;
 import android.app.Application;
 
 import com.android.launcher3.dagger.DaggerLauncherAppComponent;
+import com.android.launcher3.dagger.LauncherAppComponent;
 import com.android.launcher3.dagger.LauncherBaseAppComponent;
 
 /**
@@ -30,10 +31,18 @@ public class LauncherApplication extends Application {
     public void onCreate() {
         super.onCreate();
         MainProcessInitializer.initialize(this);
-        mAppComponent = DaggerLauncherAppComponent.builder().appContext(this).build();
+        initDagger();
     }
 
-    public LauncherBaseAppComponent getAppComponent() {
-        return mAppComponent;
+    public LauncherAppComponent getAppComponent() {
+        // Since supertype setters will return a supertype.builder and @Component.Builder types
+        // must not have any generic types.
+        // We need to cast mAppComponent to {@link LauncherAppComponent} since appContext()
+        // method is defined in the super class LauncherBaseComponent#Builder.
+        return (LauncherAppComponent) mAppComponent;
+    }
+
+    protected void initDagger() {
+        mAppComponent = DaggerLauncherAppComponent.builder().appContext(this).build();
     }
 }