New TorusEngine onWallpaperFlagsChanged() method

This forwards the event Engine.onWallpaperFlagsChanged()

Bug: 329855848
Test: Manual

Change-Id: If0af55a32e01007acf4f90c003e0a078dfd372f7
diff --git a/toruslib/torus-core/src/main/java/com/google/android/torus/core/engine/TorusEngine.kt b/toruslib/torus-core/src/main/java/com/google/android/torus/core/engine/TorusEngine.kt
index 9685816..25850cf 100644
--- a/toruslib/torus-core/src/main/java/com/google/android/torus/core/engine/TorusEngine.kt
+++ b/toruslib/torus-core/src/main/java/com/google/android/torus/core/engine/TorusEngine.kt
@@ -16,6 +16,7 @@
 
 package com.google.android.torus.core.engine
 
+import android.app.WallpaperManager
 import com.google.android.torus.core.wallpaper.LiveWallpaper
 
 /**
@@ -59,4 +60,11 @@
      * @param isLastActiveInstance Whether this was the last Engine instance in our Service.
      */
     fun destroy(isLastActiveInstance: Boolean = true)
+
+    /**
+     * Called when the engine changes its destination flag. The destination indicates whether
+     * the wallpaper is drawn on home screen, lock screen, or both. It is a combination of
+     * [WallpaperManager.FLAG_LOCK] and/or [WallpaperManager.FLAG_SYSTEM]
+     */
+    fun onWallpaperFlagsChanged(which: Int) {}
 }
diff --git a/toruslib/torus-core/src/main/java/com/google/android/torus/core/wallpaper/LiveWallpaper.kt b/toruslib/torus-core/src/main/java/com/google/android/torus/core/wallpaper/LiveWallpaper.kt
index 9a5d96e..a86d886 100644
--- a/toruslib/torus-core/src/main/java/com/google/android/torus/core/wallpaper/LiveWallpaper.kt
+++ b/toruslib/torus-core/src/main/java/com/google/android/torus/core/wallpaper/LiveWallpaper.kt
@@ -28,7 +28,6 @@
 import android.service.wallpaper.WallpaperService
 import android.view.MotionEvent
 import android.view.SurfaceHolder
-import androidx.annotation.RequiresApi
 import com.google.android.torus.core.content.ConfigurationChangeListener
 import com.google.android.torus.core.engine.TorusEngine
 import com.google.android.torus.core.engine.listener.TorusTouchListener
@@ -398,6 +397,11 @@
             }
         }
 
+        override fun onWallpaperFlagsChanged(which: Int) {
+            super.onWallpaperFlagsChanged(which)
+            wallpaperEngine.onWallpaperFlagsChanged(which)
+        }
+
         /**
          * This is overriding a hidden API [WallpaperService.shouldZoomOutWallpaper].
          */