Add dismissal mechanism for contextual cards.

In the homepage, we should allow cards to be dismissed.

- Implement card flipping upon card long pressing.

Bug: 113783548
Test: robotests, visual
Change-Id: I2ddb498321ba5c5078d6944aa2ef32f1386bdb10

src/com/android/settings/homepage/contextualcards/ContextualCardManager.java

@@ -146,14 +146,14 @@ public class ContextualCardManager implements ContextualCardLoader.CardContentLo
         onContextualCardUpdated(cards.stream().collect(groupingBy(ContextualCard::getCardType)));
     }
 
-    void setListener(ContextualCardUpdateListener listener) {
-        mListener = listener;
-    }
-
     public ControllerRendererPool getControllerRendererPool() {
         return mControllerRendererPool;
     }
 
+    void setListener(ContextualCardUpdateListener listener) {
+        mListener = listener;
+    }
+
     static class CardContentLoaderCallbacks implements
             LoaderManager.LoaderCallbacks<List<ContextualCard>> {