Do not treat '0' as 'none' for font-size-adjust

Source/platform/fonts/FontDescription.cpp

 /*
  * Copyright (C) 2007 Nicholas Shanks <contact@nickshanks.com>
  * Copyright (C) 2008 Apple 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:
  *
  * 1.  Redistributions of source code must retain the above copyright
  *     notice, this list of conditions and the following disclaimer.
@@ skipping 142 matching lines @@
     m_historicalLigaturesState = ligatures.historical;
     m_contextualLigaturesState = ligatures.contextual;
 
     updateTypesettingFeatures();
 }
 
 float FontDescription::effectiveFontSize() const
 {
     // Ensure that the effective precision matches the font-cache precision.
     // This guarantees that the same precision is used regardless of cache status.
-    float computedOrAdjustedSize = adjustedSize() ? adjustedSize() : computedSize();
+    float computedOrAdjustedSize = hasSizeAdjust() ? adjustedSize() : computedSize();
     return floorf(computedOrAdjustedSize * FontCacheKey::precisionMultiplier()) / FontCacheKey::precisionMultiplier();
 }
 
 FontCacheKey FontDescription::cacheKey(const FontFaceCreationParams& creationParams, FontTraits desiredTraits) const
 {
     FontTraits fontTraits = desiredTraits.bitfield() ? desiredTraits : traits();
 
     unsigned options =
         static_cast<unsigned>(m_syntheticItalic) << 5 | // bit 6
         static_cast<unsigned>(m_syntheticBold) << 4 | // bit 5
@@ skipping 60 matching lines @@
 
         if (discretionaryLigaturesState() == FontDescription::EnabledLigaturesState
             || historicalLigaturesState() == FontDescription::EnabledLigaturesState
             || contextualLigaturesState() == FontDescription::EnabledLigaturesState) {
             m_typesettingFeatures |= blink::Ligatures;
         }
     }
 }
 
 } // namespace blink