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

Source/platform/fonts/FontDescription.cpp

Index: Source/platform/fonts/FontDescription.cpp
diff --git a/Source/platform/fonts/FontDescription.cpp b/Source/platform/fonts/FontDescription.cpp
index 647fa0da0d5180675529c51118b1b53709cec780..3cf71204176eb6e92860697d4aba2939926362dd 100644
--- a/Source/platform/fonts/FontDescription.cpp
+++ b/Source/platform/fonts/FontDescription.cpp
@@ -160,7 +160,7 @@ 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();
 }