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

Source/core/paint/DeprecatedPaintLayer.cpp

Index: Source/core/paint/DeprecatedPaintLayer.cpp
diff --git a/Source/core/paint/DeprecatedPaintLayer.cpp b/Source/core/paint/DeprecatedPaintLayer.cpp
index a7f62fdf05878ef7e08871febc7ff75416491108..abb6192e5e4a6fa41c10e4864cf33be18f591d1f 100644
--- a/Source/core/paint/DeprecatedPaintLayer.cpp
+++ b/Source/core/paint/DeprecatedPaintLayer.cpp
@@ -783,7 +783,7 @@ bool DeprecatedPaintLayer::updateLayerPosition()
             localPoint -= offset;
         }
 
-        if (positionedParent->layoutObject()->isRelPositioned() && positionedParent->layoutObject()->isLayoutInline()) {
+        if (positionedParent->layoutObject()->isInFlowPositioned() && positionedParent->layoutObject()->isLayoutInline()) {
             LayoutSize offset = toLayoutInline(positionedParent->layoutObject())->offsetForInFlowPositionedInline(*toLayoutBox(layoutObject()));
             localPoint += offset;
         }
@@ -793,7 +793,7 @@ bool DeprecatedPaintLayer::updateLayerPosition()
     }
 
     bool positionOrOffsetChanged = false;
-    if (layoutObject()->isRelPositioned()) {
+    if (layoutObject()->isInFlowPositioned()) {
         LayoutSize newOffset = layoutObject()->offsetForInFlowPosition();
         positionOrOffsetChanged = newOffset != m_offsetForInFlowPosition;
         m_offsetForInFlowPosition = newOffset;