Fixed OneTimeListener so AUTOFILL_SAVE_UI metric is properly saved.

Test: adb shell logcat -b events | grep sysui
Test: atest CtsAutoFillServiceTestCases # to make sure it didn't break anything

Fixes: 112315388

Change-Id: Iecf374578b33a4fcfa84fe4f07613e05c9777fa9
(cherry picked from commit 373d49ebe8)

services/autofill/java/com/android/server/autofill/ui/SaveUi.java

@@ -81,6 +81,13 @@ final class SaveUi {
         void onDestroy();
     }
 
+    /**
+     * Wrapper that guarantees that only one callback is triggered by ignoring further calls after
+     * it's destroyed.
+     *
+     * <p>It's needed becase {@link #onCancel(IntentSender)} is always called when the Save UI
+     * dialog is dismissed.
+     */
     private class OneTimeListener implements OnSaveListener {
 
         private final OnSaveListener mRealListener;
@@ -96,7 +103,6 @@ final class SaveUi {
             if (mDone) {
                 return;
             }
-            mDone = true;
             mRealListener.onSave();
         }
 
@@ -106,7 +112,6 @@ final class SaveUi {
             if (mDone) {
                 return;
             }
-            mDone = true;
             mRealListener.onCancel(listener);
         }