Only make home opaque when requesting visible behind false.

Bug: 26945608
Change-Id: I11273654c27a2847ca8ec9ac16823672e5d3fbe7

services/core/java/com/android/server/am/ActivityStackSupervisor.java

@@ -2606,9 +2606,11 @@ public final class ActivityStackSupervisor implements DisplayListener {
 
         stack.setVisibleBehindActivity(visible ? r : null);
         if (!visible) {
-            // Make the activity immediately above r opaque.
+            // If there is a translucent home activity, we need to force it stop being translucent,
+            // because we can't depend on the application to necessarily perform that operation.
+            // Check out b/14469711 for details.
             final ActivityRecord next = stack.findNextTranslucentActivity(r);
-            if (next != null) {
+            if (next != null && next.isHomeActivity()) {
                 mService.convertFromTranslucent(next.appToken);
             }
         }