Cleanup: Only need one bit (not two) to express flow thread state.

Source/core/layout/LayoutInline.cpp

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  * Copyright (C) 2003, 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.
  *
@@ skipping 342 matching lines @@
 
     LayoutBoxModelObject::addChild(newChild, beforeChild);
 
     newChild->setNeedsLayoutAndPrefWidthsRecalcAndFullPaintInvalidation(LayoutInvalidationReason::ChildChanged);
 }
 
 LayoutInline* LayoutInline::clone() const
 {
     LayoutInline* cloneInline = new LayoutInline(node());
     cloneInline->setStyle(mutableStyle());
-    cloneInline->setFlowThreadState(flowThreadState());
+    cloneInline->setIsInsideFlowThread(isInsideFlowThread());
     return cloneInline;
 }
 
 void LayoutInline::moveChildrenToIgnoringContinuation(LayoutInline* to, LayoutObject* startChild)
 {
     LayoutObject* child = startChild;
     while (child) {
         LayoutObject* currentChild = child;
         child = currentChild->nextSibling();
         to->addChildIgnoringContinuation(children()->removeChildNode(this, currentChild), nullptr);
@@ skipping 1075 matching lines @@
 }
 
 void LayoutInline::invalidateDisplayItemClients(const LayoutBoxModelObject& paintInvalidationContainer) const
 {
     LayoutBoxModelObject::invalidateDisplayItemClients(paintInvalidationContainer);
     for (InlineFlowBox* box = firstLineBox(); box; box = box->nextLineBox())
         paintInvalidationContainer.invalidateDisplayItemClientOnBacking(*box);
 }
 
 } // namespace blink