Separate repaint and layout requirements of StyleDifference (Step 1)

Source/core/rendering/RenderFlexibleBox.cpp

 /*
  * Copyright (C) 2011 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 195 matching lines @@
 void RenderFlexibleBox::removeChild(RenderObject* child)
 {
     RenderBlock::removeChild(child);
     m_intrinsicSizeAlongMainAxis.remove(child);
 }
 
 void RenderFlexibleBox::styleDidChange(StyleDifference diff, const RenderStyle* oldStyle)
 {
     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()) {
             ItemPosition previousAlignment = resolveAlignment(oldStyle, child->style());
             if (previousAlignment == ItemPositionStretch && previousAlignment != resolveAlignment(style(), child->style()))
                 child->setChildNeedsLayout(MarkOnlyThis);
         }
     }
 }
 
@@ skipping 1168 matching lines @@
             ASSERT(child);
             LayoutUnit lineCrossAxisExtent = lineContexts[lineNumber].crossAxisExtent;
             LayoutUnit originalOffset = lineContexts[lineNumber].crossAxisOffset - crossAxisStartEdge;
             LayoutUnit newOffset = contentExtent - originalOffset - lineCrossAxisExtent;
             adjustAlignmentForChild(child, newOffset - originalOffset);
         }
     }
 }
 
 }