Don't force full repaint on size change in style

Source/core/rendering/RenderObject.cpp

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  *           (C) 2000 Dirk Mueller (mueller@kde.org)
  *           (C) 2004 Allan Sandfeld Jensen (kde@carewolf.com)
  * Copyright (C) 2004, 2005, 2006, 2007, 2008, 2011 Apple Inc. All rights reserved.
  * Copyright (C) 2009 Google Inc. All rights reserved.
  * Copyright (C) 2009 Torch Mobile Inc. All rights reserved. (http://www.torchmobile.com/)
  *
  * This library is free software; you can redistribute it and/or
@@ skipping 1730 matching lines @@
     else if (deltaTop < 0)
         repaintUsingContainer(repaintContainer, pixelSnappedIntRect(newBounds.x(), newBounds.y(), newBounds.width(), -deltaTop), invalidationReason);
 
     LayoutUnit deltaBottom = newBounds.maxY() - oldBounds.maxY();
     if (deltaBottom > 0)
         repaintUsingContainer(repaintContainer, pixelSnappedIntRect(newBounds.x(), oldBounds.maxY(), newBounds.width(), deltaBottom), invalidationReason);
     else if (deltaBottom < 0)
         repaintUsingContainer(repaintContainer, pixelSnappedIntRect(oldBounds.x(), newBounds.maxY(), oldBounds.width(), -deltaBottom), invalidationReason);
 
     // FIXME: This is a limitation of our visual overflow being a single rectangle.
-    if (!style()->boxShadow() && !style()->hasBorderImageOutsets() && !style()->hasOutline())
+    if (!style()->hasBorder() && !style()->boxShadow() && !style()->hasBorderImageOutsets() && !style()->hasOutline())

[Julien - ping for review, 2014/06/11 17:53:24]

The border does not generate visual overflow and is already included into the
clippedOverflowRectForRepaint above so this change looks suspicious. Could you
explain why it is needed?

[Xianzhu, 2014/06/16 16:25:29]

For example, when an object with border is increasing its width, we need paint
not only the new right part, but also the old right border (to erase it).
Without this change, we'll only paint the right part, not the old right border.

Noticed this because without this change several layout tests fail because of
under-repaint of right or bottom borders.

[Julien - ping for review, 2014/06/16 20:04:24]

OK, I really think we should include the border into the regular incremental
invalidation above. The code path below should be used for _visual effects_
(which doesn't include borders).

[Xianzhu, 2014/06/16 20:49:16]

I had tried to modify regular invalidation code, but it seemed duplicate with
the code below about border. The code path below does handle border and seems to
work well for my example case. Could we reuse the code below also for border?

If we need to separate border and visual effects, should be remove
border-related code below?

         return false;
 
     // We didn't move, but we did change size. Invalidate the delta, which will consist of possibly
     // two rectangles (but typically only one).
     RenderStyle* outlineStyle = outlineStyleForRepaint();
     LayoutUnit outlineWidth = outlineStyle->outlineSize();
     LayoutBoxExtent insetShadowExtent = style()->getBoxShadowInsetExtent();
     LayoutUnit width = absoluteValue(newBounds.width() - oldBounds.width());
     if (width) {
         LayoutUnit shadowLeft;
@@ skipping 1795 matching lines @@
 {
     if (object1) {
         const WebCore::RenderObject* root = object1;
         while (root->parent())
             root = root->parent();
         root->showRenderTreeAndMark(object1, "*", object2, "-", 0);
     }
 }
 
 #endif