Better isPageLogicalHeightKnown() implementation.

third_party/WebKit/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
@@ skipping 5498 matching lines @@
 
 LayoutUnit LayoutBox::pageLogicalHeightForOffset(LayoutUnit offset) const {
   LayoutView* layoutView = view();
   LayoutFlowThread* flowThread = flowThreadContainingBlock();
   if (!flowThread)
     return layoutView->pageLogicalHeight();
   return flowThread->pageLogicalHeightForOffset(
       offset + offsetFromLogicalTopOfFirstPage());
 }
 
+bool LayoutBox::isPageLogicalHeightKnown() const {
+  if (const LayoutFlowThread* flowThread = flowThreadContainingBlock())
+    return flowThread->isPageLogicalHeightKnown();
+  return view()->pageLogicalHeight();
+}
+
 LayoutUnit LayoutBox::pageRemainingLogicalHeightForOffset(
     LayoutUnit offset,
     PageBoundaryRule pageBoundaryRule) const {
   LayoutView* layoutView = view();
   offset += offsetFromLogicalTopOfFirstPage();
 
   LayoutFlowThread* flowThread = flowThreadContainingBlock();
   if (!flowThread) {
     LayoutUnit pageLogicalHeight = layoutView->pageLogicalHeight();
     LayoutUnit remainingHeight =
@@ skipping 94 matching lines @@
   LayoutRect rect = frameRect();
 
   LayoutBlock* block = containingBlock();
   if (block)
     block->adjustChildDebugRect(rect);
 
   return rect;
 }
 
 }  // namespace blink