Destroy activity/view references to avoid memory leak

Bug: 204891006
Change-Id: If60ac1716c30ebe68fb6e7457d71f542d3075422

src/com/android/launcher3/util/ActivityLifecycleCallbacksAdapter.java

@@ -0,0 +1,29 @@
+package com.android.launcher3.util;
+
+import android.app.Activity;
+import android.app.Application.ActivityLifecycleCallbacks;
+import android.os.Bundle;
+
+public interface ActivityLifecycleCallbacksAdapter extends ActivityLifecycleCallbacks {
+
+    default void onActivityCreated(Activity activity, Bundle bundle) {
+    }
+
+    default void onActivityDestroyed(Activity activity) {
+    }
+
+    default void onActivityPaused(Activity activity) {
+    }
+
+    default void onActivityResumed(Activity activity) {
+    }
+
+    default void onActivitySaveInstanceState(Activity activity, Bundle bundle) {
+    }
+
+    default void onActivityStarted(Activity activity) {
+    }
+
+    default void onActivityStopped(Activity activity) {
+    }
+}