Center fixpos <dialog>

Source/core/rendering/RenderView.cpp

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  * Copyright (C) 2004, 2005, 2006, 2007, 2008, 2009 Apple Inc. All rights reserved.
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
  * License as published by the Free Software Foundation; either
  * version 2 of the License, or (at your option) any later version.
  *
  * This library is distributed in the hope that it will be useful,
@@ skipping 101 matching lines @@
     return RenderBlockFlow::availableLogicalHeight(heightType);
 }
 
 bool RenderView::isChildAllowed(RenderObject* child, RenderStyle*) const
 {
     return child->isBox();
 }
 
 static bool canCenterDialog(const RenderStyle* style)
 {
-    // FIXME: We must center for FixedPosition as well.
-    return style->position() == AbsolutePosition && style->hasAutoTopAndBottom();
+    return (style->position() == AbsolutePosition || style->position() == FixedPosition) && style->hasAutoTopAndBottom();
 }
 
 void RenderView::positionDialog(RenderBox* box)
 {
     HTMLDialogElement* dialog = toHTMLDialogElement(box->node());
     if (dialog->centeringMode() == HTMLDialogElement::NotCentered)
         return;
     if (dialog->centeringMode() == HTMLDialogElement::Centered) {
         if (canCenterDialog(box->style()))
             box->setY(dialog->centeredPosition());
         return;
     }
 
     ASSERT(dialog->centeringMode() == HTMLDialogElement::NeedsCentering);
     if (!canCenterDialog(box->style())) {
         dialog->setNotCentered();
         return;
     }
     FrameView* frameView = document().view();
-    int scrollTop = frameView->scrollOffset().height();
+    LayoutUnit top = (box->style()->position() == FixedPosition) ? 0 : frameView->scrollOffset().height();
     int visibleHeight = frameView->visibleContentRect(IncludeScrollbars).height();
-    LayoutUnit top = scrollTop;
     if (box->height() < visibleHeight)
         top += (visibleHeight - box->height()) / 2;
     box->setY(top);
     dialog->setCentered(top);
 }
 
 void RenderView::positionDialogs()
 {
     TrackedRendererListHashSet* positionedDescendants = positionedObjects();
     if (!positionedDescendants)
@@ skipping 841 matching lines @@
     return viewWidth(IncludeScrollbars) / scale;
 }
 
 double RenderView::layoutViewportHeight() const
 {
     float scale = m_frameView ? m_frameView->frame().pageZoomFactor() : 1;
     return viewHeight(IncludeScrollbars) / scale;
 }
 
 } // namespace WebCore