Revert the change that remove the video layout listener.

The change causes regression on the video animation when the video view
scrolls out and back into view where it becomes blank in the
magnification settings page.

Change-Id: I6cb15ced8ddc193a01822fd5dcc50194a46a4939
Fixes: 68839840
Test: manual

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

@@ -107,8 +107,6 @@ public class ToggleScreenMagnificationPreferenceFragment extends
                     videoView.setLayoutParams(videoLp);
                     videoView.invalidate();
                     videoView.start();
-                    mVideoBackgroundView.getViewTreeObserver()
-                            .removeOnGlobalLayoutListener(mLayoutListener);
                 }
             };