Revert "SystemUI: Remove nav bar background in QS customizer"

Reason for revert: Conflicts with QPR3 changes.

This reverts commit 5ad12c4c2bc3317e521eb81c098075a90984873b.

Change-Id: I427934d9750466dd444172802ec4a55e7257262b

packages/SystemUI/res/layout/qs_customize_panel_content.xml

@@ -56,4 +56,10 @@
             android:importantForAccessibility="auto" />
     </com.android.keyguard.AlphaOptimizedLinearLayout>
 
+    <View
+        android:id="@+id/nav_bar_background"
+        android:layout_width="match_parent"
+        android:layout_height="@dimen/navigation_bar_size"
+        android:layout_gravity="bottom"
+        android:background="#ff000000" />
 </merge>

packages/SystemUI/src/com/android/systemui/qs/customize/QSCustomizer.java

@@ -93,8 +93,12 @@ public class QSCustomizer extends LinearLayout {
     }
 
     void updateNavBackDrop(Configuration newConfig, LightBarController lightBarController) {
+        View navBackdrop = findViewById(R.id.nav_bar_background);
         mIsShowingNavBackdrop = newConfig.smallestScreenWidthDp >= 600
                 || newConfig.orientation != Configuration.ORIENTATION_LANDSCAPE;
+        if (navBackdrop != null) {
+            navBackdrop.setVisibility(mIsShowingNavBackdrop ? View.VISIBLE : View.GONE);
+        }
         updateNavColors(lightBarController);
     }