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 8167ca351f47d5c7b89ad8c07e566e66749ae215..9627063471cb05901eec47ee6b8dd76ba627ed88 100644
--- a/Source/core/paint/DeprecatedPaintLayer.cpp
+++ b/Source/core/paint/DeprecatedPaintLayer.cpp
@@ -786,7 +786,7 @@ 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;
         }
@@ -796,7 +796,7 @@ bool DeprecatedPaintLayer::updateLayerPosition()
     }
 
     bool positionOrOffsetChanged = false;
-    if (layoutObject()->isRelPositioned()) {
+    if (layoutObject()->isInFlowPositioned()) {
         LayoutSize newOffset = layoutObject()->offsetForInFlowPosition();
         positionOrOffsetChanged = newOffset != m_offsetForInFlowPosition;
         m_offsetForInFlowPosition = newOffset;