pass down lifecycle methods to children

lib/android/app/src/main/java/com/reactnativenavigation/viewcontrollers/ParentController.java

@@ -52,7 +52,6 @@ public abstract class ParentController extends ViewController {
 		}
 	}
 
-
 	@Override
 	public void onDisappear() {
 		super.onDisappear();
@@ -60,4 +59,12 @@ public abstract class ParentController extends ViewController {
 			child.onDisappear();
 		}
 	}
+
+	@Override
+	public void onDestroy() {
+		super.onDestroy();
+		for (ViewController child : getChildControllers()) {
+			child.onDestroy();
+		}
+	}
 }

lib/android/app/src/test/java/com/reactnativenavigation/viewcontrollers/ParentControllerTest.java

@@ -100,4 +100,13 @@ public class ParentControllerTest extends BaseTest {
 		verify(child1, times(1)).onDisappear();
 	}
 
+	@Test
+	public void lifecycleMethodsPassDownToChildren_onDestroy() throws Exception {
+		ViewController child1 = spy(new SimpleViewController(activity, "child1"));
+		children.add(child1);
+
+		verify(child1, times(0)).onDestroy();
+		uut.onDestroy();
+		verify(child1, times(1)).onDestroy();
+	}
 }