Conditionally create PaintLayer's scrollable area object

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

 /*
  * Copyright (C) 2006, 2007, 2009 Apple Inc. All rights reserved.
  * Copyright (C) 2008 Torch Mobile Inc. All rights reserved. (http://www.torchmobile.com/)
  * Copyright (C) 2010 Nokia Corporation and/or its subsidiary(-ies).
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
  * License as published by the Free Software Foundation; either
  * version 2 of the License, or (at your option) any later version.
  *
@@ skipping 53 matching lines @@
     void setScrollLeft(LayoutUnit) final;
     void setScrollTop(LayoutUnit) final;
 
     int textBlockWidth() const;
     float getAvgCharWidth(const AtomicString& family) const final;
     LayoutUnit preferredContentLogicalWidth(float charWidth) const final;
     LayoutUnit computeControlLogicalHeight(LayoutUnit lineHeight, LayoutUnit nonContentHeight) const override;
     void styleDidChange(StyleDifference, const ComputedStyle* oldStyle) final;
     void addOverflowFromChildren() final;
 
+    bool allowsOverflowClip() const override { return false; }
+
     bool textShouldBeTruncated() const;
     HTMLElement* innerSpinButtonElement() const;
 
     bool m_shouldDrawCapsLockIndicator;
 };
 
 DEFINE_LAYOUT_OBJECT_TYPE_CASTS(LayoutTextControlSingleLine, isTextField());
 
 // ----------------------------
 
 class LayoutTextControlInnerBlock : public LayoutBlockFlow {
 public:
     LayoutTextControlInnerBlock(Element* element) : LayoutBlockFlow(element) { }
     bool shouldIgnoreOverflowPropertyForInlineBlockBaseline() const override { return true; }
 
 private:
     bool isIntrinsicallyScrollable(ScrollbarOrientation orientation) const override
     {
         return orientation == HorizontalScrollbar;
     }
     bool scrollsOverflowX() const override { return hasOverflowClip(); }
     bool scrollsOverflowY() const override { return false; }
     bool hasLineIfEmpty() const override { return true; }
 };
 
 } // namespace blink
 
 #endif