Fix nav bar visibility on lock screen

StatusBarKeyguardViewManager was assuming that the navigation bar
was the root view in its window, which it isn't anymore. Add a
getRootView() to ensure it is always the root.

Change-Id: Ifeeecc1ae8d7b6c4235a1ce4767dad3919bf90e6
Fixes: 34452399
Test: lock device, tap on nav bar area

packages/SystemUI/src/com/android/systemui/statusbar/phone/StatusBarKeyguardViewManager.java

@@ -491,7 +491,7 @@ public class StatusBarKeyguardViewManager implements RemoteInputController.Callb
     private Runnable mMakeNavigationBarVisibleRunnable = new Runnable() {
         @Override
         public void run() {
-            mPhoneStatusBar.getNavigationBarView().setVisibility(View.VISIBLE);
+            mPhoneStatusBar.getNavigationBarView().getRootView().setVisibility(View.VISIBLE);
         }
     };
 
@@ -527,7 +527,7 @@ public class StatusBarKeyguardViewManager implements RemoteInputController.Callb
                     }
                 } else {
                     mContainer.removeCallbacks(mMakeNavigationBarVisibleRunnable);
-                    mPhoneStatusBar.getNavigationBarView().setVisibility(View.GONE);
+                    mPhoneStatusBar.getNavigationBarView().getRootView().setVisibility(View.GONE);
                 }
             }
         }