Add rotary support to the nofitication shade.

- Add a FocusArea
- Add a FocusParkingView

The FocusArea's main contribution in this case is to
allow OEM customizability of the focus highlight for
the rotary feature. The UI was already in a rotary
compatible state without it (i.e. I could navigate
around even before adding this change)

BUG: 157937087
Test: manual
Change-Id: If02f9e73ca3a941fc783a63924135a2f78b12723
diff --git a/packages/CarSystemUI/res/layout/notification_center_activity.xml b/packages/CarSystemUI/res/layout/notification_center_activity.xml
index 0af74c4..0e45e43 100644
--- a/packages/CarSystemUI/res/layout/notification_center_activity.xml
+++ b/packages/CarSystemUI/res/layout/notification_center_activity.xml
@@ -22,6 +22,10 @@
     android:layout_height="match_parent"
     android:background="@color/notification_shade_background_color">
 
+    <com.android.car.ui.FocusParkingView
+        android:layout_width="wrap_content"
+        android:layout_height="wrap_content"/>
+
     <View
         android:id="@+id/glass_pane"
         android:layout_width="match_parent"
@@ -33,16 +37,20 @@
         app:layout_constraintTop_toTopOf="parent"
     />
 
-    <androidx.recyclerview.widget.RecyclerView
-        android:id="@+id/notifications"
+    <com.android.car.ui.FocusArea
         android:layout_width="0dp"
         android:layout_height="0dp"
         android:orientation="vertical"
-        android:paddingBottom="@dimen/notification_shade_list_padding_bottom"
         app:layout_constraintBottom_toBottomOf="parent"
         app:layout_constraintEnd_toEndOf="parent"
         app:layout_constraintStart_toStartOf="parent"
-        app:layout_constraintTop_toTopOf="parent"/>
+        app:layout_constraintTop_toTopOf="parent">
+        <androidx.recyclerview.widget.RecyclerView
+            android:id="@+id/notifications"
+            android:layout_width="match_parent"
+            android:layout_height="match_parent"
+            android:paddingBottom="@dimen/notification_shade_list_padding_bottom"/>
+    </com.android.car.ui.FocusArea>
 
     <include layout="@layout/notification_handle_bar"/>