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 732534714a7bd2ee4802b29946d412e7c0aaf92e..566ba5ce814f9d4fda8781acd551e8e9a8d1f528 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()) {