[css-sizing] Ensure positive available size on replaced elements

third_party/WebKit/Source/platform/Length.h

 /*
     Copyright (C) 1999 Lars Knoll (knoll@kde.org)
     Copyright (C) 2006, 2008 Apple Inc. All rights reserved.
     Copyright (C) 2011 Rik Cabanier (cabanier@adobe.com)
     Copyright (C) 2011 Adobe Systems Incorporated. All rights reserved.
 
     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 231 matching lines @@
   bool isCalculated() const { return type() == Calculated; }
   bool isCalculatedEqual(const Length&) const;
   bool isMinContent() const { return type() == MinContent; }
   bool isMaxContent() const { return type() == MaxContent; }
   bool isFillAvailable() const { return type() == FillAvailable; }
   bool isFitContent() const { return type() == FitContent; }
   bool isPercent() const { return type() == Percent; }
   bool isPercentOrCalc() const {
     return type() == Percent || type() == Calculated;
   }
+  // This group of lengths require layout because they need the containing
+  // block's available size. There might be other reasons that could imply
+  // a Length requiring a layout, but in that case we should re-define the
+  // function that groups all these Lengths.
+  bool isLayoutDependent() const {
+    return isPercentOrCalc() || isFillAvailable() || isFitContent();
+  }
 
   Length blend(const Length& from, double progress, ValueRange range) const {
     ASSERT(isSpecified() && from.isSpecified());
 
     if (progress == 0.0)
       return from;
 
     if (progress == 1.0)
       return *this;
 
@@ skipping 46 matching lines @@
     float m_floatValue;
   };
   bool m_quirk;
   unsigned char m_type;
   bool m_isFloat;
 };
 
 }  // namespace blink
 
 #endif  // Length_h