Add Nullability annotations for Notification.Action.Builder methods.

Bug: 128704087
Test: make
Change-Id: Id69837cde581297cc9e1e449f00d492b067bf771
diff --git a/core/java/android/app/Notification.java b/core/java/android/app/Notification.java
index a8a34d2..33b41c4 100644
--- a/core/java/android/app/Notification.java
+++ b/core/java/android/app/Notification.java
@@ -1569,12 +1569,12 @@
          * Builder class for {@link Action} objects.
          */
         public static final class Builder {
-            private final Icon mIcon;
-            private final CharSequence mTitle;
-            private final PendingIntent mIntent;
+            @Nullable private final Icon mIcon;
+            @Nullable private final CharSequence mTitle;
+            @Nullable private final PendingIntent mIntent;
             private boolean mAllowGeneratedReplies = true;
-            private final Bundle mExtras;
-            private ArrayList<RemoteInput> mRemoteInputs;
+            @NonNull private final Bundle mExtras;
+            @Nullable private ArrayList<RemoteInput> mRemoteInputs;
             private @SemanticAction int mSemanticAction;
             private boolean mIsContextual;
 
@@ -1610,9 +1610,10 @@
                         action.getAllowGeneratedReplies(), action.getSemanticAction());
             }
 
-            private Builder(Icon icon, CharSequence title, PendingIntent intent, Bundle extras,
-                    RemoteInput[] remoteInputs, boolean allowGeneratedReplies,
-                            @SemanticAction int semanticAction) {
+            private Builder(@Nullable Icon icon, @Nullable CharSequence title,
+                    @Nullable PendingIntent intent, @NonNull Bundle extras,
+                    @Nullable RemoteInput[] remoteInputs, boolean allowGeneratedReplies,
+                    @SemanticAction int semanticAction) {
                 mIcon = icon;
                 mTitle = title;
                 mIntent = intent;
@@ -1645,6 +1646,7 @@
              *
              * <p>The returned Bundle is shared with this Builder.
              */
+            @NonNull
             public Bundle getExtras() {
                 return mExtras;
             }