Make ZenPolicy.Builder a final static inner class

Fixes: 126698794
Test: atest ZenPolicyTest
Change-Id: I847831136fa017419eba3a00ce31091cfdb08d45
diff --git a/api/current.txt b/api/current.txt
index 12b4d4b..be4ef7b 100644
--- a/api/current.txt
+++ b/api/current.txt
@@ -41870,7 +41870,7 @@
     field public static final int STATE_UNSET = 0; // 0x0
   }
 
-  public static class ZenPolicy.Builder {
+  public static final class ZenPolicy.Builder {
     ctor public ZenPolicy.Builder();
     method @NonNull public android.service.notification.ZenPolicy.Builder allowAlarms(boolean);
     method @NonNull public android.service.notification.ZenPolicy.Builder allowAllSounds();
diff --git a/core/java/android/service/notification/ZenPolicy.java b/core/java/android/service/notification/ZenPolicy.java
index 7ef40cd..9694998 100644
--- a/core/java/android/service/notification/ZenPolicy.java
+++ b/core/java/android/service/notification/ZenPolicy.java
@@ -358,7 +358,7 @@
      * Provides a convenient way to set the various fields of a {@link ZenPolicy}.  If a field
      * is not set, it is (@link STATE_UNSET} and will not change the current set policy.
      */
-    public static class Builder {
+    public static final class Builder {
         private ZenPolicy mZenPolicy;
 
         public Builder() {