[css-flexbox] Clear override sizes when we're no longer a flex item

third_party/WebKit/Source/core/layout/LayoutBox.cpp

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  *           (C) 2005 Allan Sandfeld Jensen (kde@carewolf.com)
  *           (C) 2005, 2006 Samuel Weinig (sam.weinig@gmail.com)
  * Copyright (C) 2005, 2006, 2007, 2008, 2009, 2010 Apple Inc.
  *               All rights reserved.
  * Copyright (C) 2013 Adobe Systems Incorporated. All rights reserved.
  *
  * This library is free software; you can redistribute it and/or
@@ skipping 294 matching lines @@
           scrollableArea->horizontalScrollbar()->styleChanged();
         if (scrollableArea->verticalScrollbar() &&
             scrollableArea->verticalScrollbar()->isCustomScrollbar())
           scrollableArea->verticalScrollbar()->styleChanged();
       }
     }
   }
   updateShapeOutsideInfoAfterStyleChange(*style(), oldStyle);
   updateGridPositionAfterStyleChange(oldStyle);
 
+  // When we're no longer a flex item because we're now absolutely positioned,
+  // we need to clear the override size so we're not affected by it anymore.
+  // This technically covers too many cases (even when out-of-flow did not
+  // change) but that should be harmless.
+  if (isOutOfFlowPositioned() && parent() &&
+      parent()->styleRef().isDisplayFlexibleOrGridBox())
+    clearOverrideSize();
+
   if (LayoutMultiColumnSpannerPlaceholder* placeholder =
           this->spannerPlaceholder())
     placeholder->layoutObjectInFlowThreadStyleDidChange(oldStyle);
 
   updateBackgroundAttachmentFixedStatusAfterStyleChange();
 
   if (oldStyle) {
     LayoutFlowThread* flowThread = flowThreadContainingBlock();
     if (flowThread && flowThread != this)
       flowThread->flowThreadDescendantStyleDidChange(this, diff, *oldStyle);
@@ skipping 5368 matching lines @@
     block->adjustChildDebugRect(rect);
 
   return rect;
 }
 
 bool LayoutBox::shouldClipOverflow() const {
   return hasOverflowClip() || styleRef().containsPaint() || hasControlClip();
 }
 
 }  // namespace blink