Add position: sticky as supported position value when CSSStickyPosition is enabled.

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 126 matching lines @@
     setInline(true);
 
     // FIXME: Support transforms and reflections on inline flows someday.
     setHasTransformRelatedProperty(false);
     setHasReflection(false);
 }
 
 static LayoutObject* inFlowPositionedInlineAncestor(LayoutObject* p)
 {
     while (p && p->isLayoutInline()) {
-        if (p->isRelPositioned())
+        if (p->isInFlowPositioned())
             return p;
         p = p->parent();
     }
     return nullptr;
 }
 
 static void updateStyleOfAnonymousBlockContinuations(LayoutObject* block, const ComputedStyle& newStyle, const ComputedStyle& oldStyle, LayoutObject* containingBlockOfEndOfContinuation)
 {
     // If an inline's outline or in-flow positioning has changed then any descendant blocks will need to change their styles accordingly.
     bool updateOutline = !newStyle.isOutlineEquivalent(&oldStyle);
@@ skipping 964 matching lines @@
     }
 
     o->mapRectToPaintInvalidationBacking(paintInvalidationContainer, rect, paintInvalidationState);
 }
 
 LayoutSize LayoutInline::offsetFromContainer(const LayoutObject* container, const LayoutPoint& point, bool* offsetDependsOnPoint) const
 {
     ASSERT(container == this->container());
 
     LayoutSize offset;
-    if (isRelPositioned())
+    if (isInFlowPositioned())
         offset += offsetForInFlowPosition();
 
     offset += container->columnOffset(point);
 
     if (container->hasOverflowClip())
         offset -= toLayoutBox(container)->scrolledContentOffset();
 
     if (offsetDependsOnPoint)
         *offsetDependsOnPoint = (container->isBox() && container->style()->isFlippedBlocksWritingMode()) || container->isLayoutFlowThread();
 
@@ skipping 149 matching lines @@
 {
     ASSERT(linePositionMode == PositionOnContainingLine);
     const FontMetrics& fontMetrics = style(firstLine)->fontMetrics();
     return fontMetrics.ascent(baselineType) + (lineHeight(firstLine, direction, linePositionMode) - fontMetrics.height()) / 2;
 }
 
 LayoutSize LayoutInline::offsetForInFlowPositionedInline(const LayoutBox& child) const
 {
     // FIXME: This function isn't right with mixed writing modes.
 
-    ASSERT(isRelPositioned());
-    if (!isRelPositioned())
+    ASSERT(isInFlowPositioned());
+    if (!isInFlowPositioned())
         return LayoutSize();
 
     // When we have an enclosing relpositioned inline, we need to add in the offset of the first line
     // box from the rest of the content, but only in the cases where we know we're positioned
     // relative to the inline itself.
 
     LayoutSize logicalOffset;
     LayoutUnit inlinePosition;
     LayoutUnit blockPosition;
     if (firstLineBox()) {
@@ skipping 112 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