More fixes for position:fixed with root layer scrolling.

Source/core/layout/LayoutBox.cpp

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  *           (C) 2005 Allan Sandfeld Jensen (kde@carewolf.com)
  *           (C) 2005, 2006 Samuel Weinig (sam.weinig@gmail.com)
  * Copyright (C) 2005, 2006, 2007, 2008, 2009, 2010 Apple Inc. All rights reserved.
  * Copyright (C) 2013 Adobe Systems Incorporated. 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
@@ skipping 2691 matching lines @@
 
 LayoutUnit LayoutBox::containingBlockLogicalWidthForPositioned(const LayoutBoxModelObject* containingBlock, bool checkForPerpendicularWritingMode) const
 {
     if (checkForPerpendicularWritingMode && containingBlock->isHorizontalWritingMode() != isHorizontalWritingMode())
         return containingBlockLogicalHeightForPositioned(containingBlock, false);
 
     // Use viewport as container for top-level fixed-position elements.
     if (style()->position() == FixedPosition && containingBlock->isLayoutView()) {
         const LayoutView* view = toLayoutView(containingBlock);
         if (FrameView* frameView = view->frameView()) {
-            LayoutRect viewportRect = LayoutRect(frameView->visibleContentRect());
-            return containingBlock->isHorizontalWritingMode() ? viewportRect.width() : viewportRect.height();
+            // Don't use visibleContentRect since the DeprecatedPaintLayer's size has not been set yet.
+            IntSize viewportSize = frameView->layoutViewportScrollableArea()->excludeScrollbars(frameView->frameRect().size());
+            return containingBlock->isHorizontalWritingMode() ? viewportSize.width() : viewportSize.height();
         }
     }
 
     if (hasOverrideContainingBlockLogicalWidth())
         return overrideContainingBlockContentLogicalWidth();
 
     if (containingBlock->isBox())
         return toLayoutBox(containingBlock)->clientLogicalWidth();
 
     ASSERT(containingBlock->isLayoutInline() && containingBlock->isRelPositioned());
@@ skipping 21 matching lines @@
 
 LayoutUnit LayoutBox::containingBlockLogicalHeightForPositioned(const LayoutBoxModelObject* containingBlock, bool checkForPerpendicularWritingMode) const
 {
     if (checkForPerpendicularWritingMode && containingBlock->isHorizontalWritingMode() != isHorizontalWritingMode())
         return containingBlockLogicalWidthForPositioned(containingBlock, false);
 
     // Use viewport as container for top-level fixed-position elements.
     if (style()->position() == FixedPosition && containingBlock->isLayoutView()) {
         const LayoutView* view = toLayoutView(containingBlock);
         if (FrameView* frameView = view->frameView()) {
-            LayoutRect viewportRect = LayoutRect(frameView->visibleContentRect());
-            return containingBlock->isHorizontalWritingMode() ? viewportRect.height() : viewportRect.width();
+            // Don't use visibleContentRect since the DeprecatedPaintLayer's size has not been set yet.
+            IntSize viewportSize = frameView->layoutViewportScrollableArea()->excludeScrollbars(frameView->frameRect().size());
+            return containingBlock->isHorizontalWritingMode() ? viewportSize.height() : viewportSize.width();
         }
     }
 
     if (hasOverrideContainingBlockLogicalHeight())
         return overrideContainingBlockContentLogicalHeight();
 
     if (containingBlock->isBox()) {
         const LayoutBlock* cb = containingBlock->isLayoutBlock() ?
             toLayoutBlock(containingBlock) : containingBlock->containingBlock();
         return cb->clientLogicalHeight();
@@ skipping 1981 matching lines @@
 bool LayoutBox::canRenderBorderImage() const
 {
     if (!style()->hasBorderDecoration())
         return false;
 
     StyleImage* borderImage = style()->borderImage().image();
     return borderImage && borderImage->canRender(*this, style()->effectiveZoom()) && borderImage->isLoaded();
 }
 
 } // namespace blink