getComputedStyle() should return used value for 'line-height'

third_party/WebKit/Source/core/css/ComputedStyleCSSValueMapping.cpp

 /*
  * Copyright (C) 2004 Zack Rusin <zack@kde.org>
  * Copyright (C) 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2011, 2012 Apple Inc. All rights reserved.
  * Copyright (C) 2007 Alexey Proskuryakov <ap@webkit.org>
  * Copyright (C) 2007 Nicholas Shanks <webkit@nickshanks.com>
  * Copyright (C) 2011 Sencha, Inc. All rights reserved.
  * Copyright (C) 2015 Google Inc. All rights reserved.
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Lesser General Public
@@ skipping 443 matching lines @@
         result->append(CSSPrimitiveValue::create(data.position()));
     if ((data.position() >= ContentPositionCenter || data.distribution() != ContentDistributionDefault) && data.overflow() != OverflowAlignmentDefault)
         result->append(CSSPrimitiveValue::create(data.overflow()));
     ASSERT(result->length() > 0);
     ASSERT(result->length() <= 3);
     return result.release();
 }
 
 static PassRefPtrWillBeRawPtr<CSSPrimitiveValue> valueForLineHeight(const ComputedStyle& style)
 {
-    Length length = style.lineHeight();
+    Length length = Length(style.computedLineHeight(), Fixed);
     if (length.isNegative())
         return cssValuePool().createIdentifierValue(CSSValueNormal);
 
     return zoomAdjustedPixelValue(floatValueForLength(length, style.getFontDescription().computedSize()), style);

[Timothy Loh, 2016/03/21 05:56:20]

floatValueForLength resolves percentages but if you create a Length(Fixed) then
there are no percentages. Do we need to create a Length at all?

[nainar, 2016/03/21 06:21:45]

No. You're right we can also omit the check for isNegative() in that case.
computedLineHeight deals with the negative case. 

 }
 
 static CSSValueID identifierForFamily(const AtomicString& family)
 {
     if (family == FontFamilyNames::webkit_cursive)
         return CSSValueCursive;
     if (family == FontFamilyNames::webkit_fantasy)
         return CSSValueFantasy;
     if (family == FontFamilyNames::webkit_monospace)
         return CSSValueMonospace;
@@ skipping 2275 matching lines @@
     case CSSPropertyAll:
         return nullptr;
     default:
         break;
     }
     ASSERT_NOT_REACHED();
     return nullptr;
 }
 
 } // namespace blink