Cleanup: Get rid of LayoutBlock::offsetFromLogicalTopOfFirstPage().

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 4626 matching lines @@
     if (didSplitParentAnonymousBoxes)
         markBoxForRelayoutAfterSplit(this);
 
     ASSERT(beforeChild->parent() == this);
     return beforeChild;
 }
 
 LayoutUnit LayoutBox::offsetFromLogicalTopOfFirstPage() const
 {
     LayoutState* layoutState = view()->layoutState();
-    if (layoutState && !layoutState->isPaginated())
+    if (!layoutState || !layoutState->isPaginated())
         return LayoutUnit();
 
-    if (!layoutState && !flowThreadContainingBlock())
-        return LayoutUnit();
+    if (layoutState->layoutObject() == this) {
+        LayoutSize offsetDelta = layoutState->layoutOffset() - layoutState->pageOffset();
+        return isHorizontalWritingMode() ? offsetDelta.height() : offsetDelta.width();
+    }
 
+    // A LayoutBlock always establishes a layout state, and this method is only meant to be called
+    // on the object currently being laid out.
+    ASSERT(!isLayoutBlock());
+
+    // In case this box doesn't establish a layout state, try the containing block.
     LayoutBlock* containerBlock = containingBlock();
+    ASSERT(layoutState->layoutObject() == containerBlock);
     return containerBlock->offsetFromLogicalTopOfFirstPage() + logicalTop();
 }
 
 void LayoutBox::savePreviousBorderBoxSizeIfNeeded()
 {
     // If m_rareData is already created, always save.
     if (!m_rareData) {
         LayoutSize paintInvalidationSize = previousPaintInvalidationRect().size();
 
         // Don't save old border box size if the paint rect is empty because we'll
@@ skipping 130 matching lines @@
 bool LayoutBox::canRenderBorderImage() const
 {
     if (!style()->hasBorder())
         return false;
 
     StyleImage* borderImage = style()->borderImage().image();
     return borderImage && borderImage->canRender(*this, style()->effectiveZoom()) && borderImage->isLoaded();
 }
 
 } // namespace blink