Fix scroll origin, overflow rects, and coordinate flipping for flexbox.

third_party/WebKit/Source/core/layout/LayoutFlexibleBox.h

 /*
  * 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 35 matching lines @@
 
     const char* name() const override { return "LayoutFlexibleBox"; }
 
     bool isFlexibleBox() const final { return true; }
     bool canCollapseAnonymousBlockChild() const override { return false; }
     void layoutBlock(bool relayoutChildren) final;
 
     int baselinePosition(FontBaseline, bool firstLine, LineDirectionMode, LinePositionMode = PositionOnContainingLine) const override;
     int firstLineBoxBaseline() const override;
     int inlineBlockBaseline(LineDirectionMode) const override;
+    IntSize originAdjustmentForScrollbars() const override;
+    bool hasTopOverflow() const override;
+    bool hasLeftOverflow() const override;
 
     void paintChildren(const PaintInfo&, const LayoutPoint&) const final;
 
     bool isHorizontalFlow() const;
 
     const OrderIterator& orderIterator() const { return m_orderIterator; }
 
     // Returns -1 if the height of this flexbox is indefinite
     LayoutUnit computeDefiniteLogicalWidth();
     LayoutUnit computeDefiniteLogicalHeight();
@@ skipping 138 matching lines @@
 
     mutable OrderIterator m_orderIterator;
     int m_numberOfInFlowChildrenOnFirstLine;
 };
 
 DEFINE_LAYOUT_OBJECT_TYPE_CASTS(LayoutFlexibleBox, isFlexibleBox());
 
 } // namespace blink
 
 #endif // LayoutFlexibleBox_h