Merge "Fix the display/Font preview window appears blank while transitioning between sizes."

src/com/android/settings/accessibility/PreviewSizeSeekBarController.java

@@ -48,7 +48,9 @@ class PreviewSizeSeekBarController extends BasePreferenceController implements
 
                     final ProgressInteractionListener interactionListener =
                             mInteractionListener.get();
-                    interactionListener.notifyPreferenceChanged();
+                    // Avoid timing issues to update the corresponding preview fail when clicking
+                    // the increase/decrease button.
+                    seekBar.post(interactionListener::notifyPreferenceChanged);
 
                     if (!mSeekByTouch) {
                         interactionListener.onProgressChanged();