Fix integer overflow in ComputedStyle::computedLineHeight

Source/core/style/ComputedStyle.cpp

 /*
  * Copyright (C) 1999 Antti Koivisto (koivisto@kde.org)
  * Copyright (C) 2004, 2005, 2006, 2007, 2008, 2009, 2010 Apple Inc. All rights reserved.
  * 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 1227 matching lines @@
     // too, though this involves messily poking into CalcExpressionLength.
     float multiplier = textAutosizingMultiplier();
     if (multiplier > 1 && lh.isFixed())
         return Length(TextAutosizer::computeAutosizedFontSize(lh.value(), multiplier), Fixed);
 
     return lh;
 }
 
 void ComputedStyle::setLineHeight(const Length& specifiedLineHeight) { SET_VAR(inherited, line_height, specifiedLineHeight); }
 
-int ComputedStyle::computedLineHeight() const
+LayoutUnit ComputedStyle::computedLineHeight() const
 {
     const Length& lh = lineHeight();
 
     // Negative value means the line height is not set. Use the font's built-in spacing.
     if (lh.isNegative())
         return fontMetrics().lineSpacing();
 
     if (lh.isPercent())
         return minimumValueForLength(lh, fontSize());
 
-    return lh.value();
+    return truncf(lh.value());

[Bem Jones-Bey (adobe), 2015/04/02 21:53:14]

Why do we have to explicitly truncf here? Does the LayoutUnit constructor not do
the right thing?

 }
 
 void ComputedStyle::setWordSpacing(float wordSpacing)
 {
     FontSelector* currentFontSelector = font().fontSelector();
     FontDescription desc(fontDescription());
     desc.setWordSpacing(wordSpacing);
     setFontDescription(desc);
     font().update(currentFontSelector);
 }
@@ skipping 452 matching lines @@
         horizontal || includeLogicalRightEdge);
 
     edges[BSLeft] = BorderEdge(borderLeftWidth(),
         visitedDependentColor(CSSPropertyBorderLeftColor),
         borderLeftStyle(),
         borderLeftIsTransparent(),
         !horizontal || includeLogicalLeftEdge);
 }
 
 } // namespace blink