Separate repaint and layout requirements of StyleDifference (Step 1)

Source/core/rendering/RenderFlexibleBox.cpp

Index: Source/core/rendering/RenderFlexibleBox.cpp
diff --git a/Source/core/rendering/RenderFlexibleBox.cpp b/Source/core/rendering/RenderFlexibleBox.cpp
index fa0315b4d75988c0cc81808e10692c9428f30819..aa4c8f483e25e359591432c1578e6f578319aa06 100644
--- a/Source/core/rendering/RenderFlexibleBox.cpp
+++ b/Source/core/rendering/RenderFlexibleBox.cpp
@@ -213,7 +213,7 @@ void RenderFlexibleBox::styleDidChange(StyleDifference diff, const RenderStyle*
 {
     RenderBlock::styleDidChange(diff, oldStyle);
 
-    if (oldStyle && oldStyle->alignItems() == ItemPositionStretch && diff == StyleDifferenceLayout) {
+    if (oldStyle && oldStyle->alignItems() == ItemPositionStretch && diff.needsFullLayout()) {
         // Flex items that were previously stretching need to be relayed out so we can compute new available cross axis space.
         // This is only necessary for stretching since other alignment values don't change the size of the box.
         for (RenderBox* child = firstChildBox(); child; child = child->nextSiblingBox()) {