8311805: Clean up ScrollPane: drop redundant initialiser, mark scroll…

…er final

Reviewed-by: azvegint, serb, prr

src/java.desktop/share/classes/java/awt/ScrollPane.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 1996, 2021, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 1996, 2023, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -507,7 +507,6 @@ public void layout() {
  Component c = getComponent(0);
  Point p = getScrollPosition();
  Dimension cs = calculateChildSize();
- Dimension vs = getViewportSize();
 
  c.reshape(- p.x, - p.y, cs.width, cs.height);
  ScrollPanePeer peer = (ScrollPanePeer)this.peer;
@@ -518,7 +517,7 @@ public void layout() {
  // update adjustables... the viewport size may have changed
  // with the scrollbars coming or going so the viewport size
  // is updated before the adjustables.
- vs = getViewportSize();
+ Dimension vs = getViewportSize();
  hAdjustable.setSpan(0, cs.width, vs.width);
  vAdjustable.setSpan(0, cs.height, vs.height);
  }
@@ -776,7 +775,7 @@ public void adjustmentValueChanged(AdjustmentEvent e) {
  }
  }
 
- private ScrollPane scroller;
+ private final ScrollPane scroller;
  }