Add a PendingIntent flag to mark unaudited PI mutability

This change adds a FLAG_MUTABLE_UNAUDITED that is equal in value to
FLAG_MUTABLE but is intended to be used with PendingIntents that have
not yet been audited to be intentionally mutable/immutable. This will
help us update the tree to work with the enforced explicit mutability flag
requirement (go/immutable-pendingintents has more context).

This flag is marked as deprecated and we hope to remove it once all PIs
have been audited and use either FLAG_MUTABLE or FLAG_IMMUTABLE.
FLAG_MUTABLE_UNAUDITED should not be relied on long term, and any usage
is intended to be short term.

Bug: 160794467
Test: TH
Change-Id: I6a4f65d5364a611620b88e92c208aba7faaa13b8

core/java/android/app/PendingIntent.java

@@ -130,6 +130,7 @@ public final class PendingIntent implements Parcelable {
                     FLAG_UPDATE_CURRENT,
                     FLAG_IMMUTABLE,
                     FLAG_MUTABLE,
+                    FLAG_MUTABLE_UNAUDITED,
 
                     Intent.FILL_IN_ACTION,
                     Intent.FILL_IN_DATA,
@@ -204,6 +205,13 @@ public final class PendingIntent implements Parcelable {
      */
     public static final int FLAG_MUTABLE = 1<<25;
 
+    /**
+     * @deprecated Use {@link #FLAG_IMMUTABLE} or {@link #FLAG_MUTABLE} instead.
+     * @hide
+     */
+    @Deprecated
+    public static final int FLAG_MUTABLE_UNAUDITED = FLAG_MUTABLE;
+
     /**
      * Exception thrown when trying to send through a PendingIntent that
      * has been canceled or is otherwise no longer able to execute the request.