Clarified FillCallback and SaveCallback behaviors.

Test: mmm -j frameworks/base/:doc-comment-check-docs

Bug: 116103297

Change-Id: Ib397556007d1f8bf6d5d08c6bf2edf69f88b7f07
diff --git a/core/java/android/service/autofill/SaveCallback.java b/core/java/android/service/autofill/SaveCallback.java
index 855981a..a98a249 100644
--- a/core/java/android/service/autofill/SaveCallback.java
+++ b/core/java/android/service/autofill/SaveCallback.java
@@ -41,6 +41,9 @@
      * Notifies the Android System that an
      * {@link AutofillService#onSaveRequest(SaveRequest, SaveCallback)} was successfully handled
      * by the service.
+     *
+     * @throws IllegalStateException if this method, {@link #onSuccess(IntentSender)}, or
+     * {@link #onFailure(CharSequence)} was already called.
      */
     public void onSuccess() {
         onSuccessInternal(null);
@@ -58,6 +61,9 @@
      *
      * @param intentSender intent that will be launched from the context of activity being
      * autofilled.
+     *
+     * @throws IllegalStateException if this method, {@link #onSuccess()},
+     * or {@link #onFailure(CharSequence)} was already called.
      */
     public void onSuccess(@NonNull IntentSender intentSender) {
         onSuccessInternal(Preconditions.checkNotNull(intentSender));
@@ -86,7 +92,12 @@
      * you prefer to show your own message, call {@link #onSuccess()} or
      * {@link #onSuccess(IntentSender)} instead.
      *
-     * @param message error message to be displayed to the user.
+     * @param message error message to be displayed to the user. <b>Note: </b> this message is
+     * displayed on {@code logcat} logs and should not contain PII (Personally Identifiable
+     * Information, such as username or email address).
+     *
+     * @throws IllegalStateException if this method, {@link #onSuccess()},
+     * or {@link #onSuccess(IntentSender)} was already called.
      */
     public void onFailure(CharSequence message) {
         assertNotCalled();