Bug fix - rem & ch in MQs/sizes treated as unknown units

Source/core/css/MediaQueryExp.cpp

Index: Source/core/css/MediaQueryExp.cpp
diff --git a/Source/core/css/MediaQueryExp.cpp b/Source/core/css/MediaQueryExp.cpp
index 253350d1da9e82a17d88230d3e71f61a8302ebcb..798fafe20d6a0bdb3cf385b78169e4c0c92c1e1f 100644
--- a/Source/core/css/MediaQueryExp.cpp
+++ b/Source/core/css/MediaQueryExp.cpp
@@ -67,9 +67,15 @@ static inline bool featureWithValidIdent(const String& mediaFeature, CSSValueID
     return false;
 }
 
+static bool positiveLengthUnit(const int unit)
+{
+    return ((unit >= CSSPrimitiveValue::CSS_EMS && unit <= CSSPrimitiveValue::CSS_PC)
+        || unit == CSSPrimitiveValue::CSS_REMS || unit == CSSPrimitiveValue::CSS_CHS);

[alancutter (OOO until 2018), 2014/07/29 03:25:15]

A switch would be more explicit and readable here.

+}
+
 static inline bool featureWithValidPositiveLength(const String& mediaFeature, const CSSParserValue* value)
 {
-    if (!(((value->unit >= CSSPrimitiveValue::CSS_EMS && value->unit <= CSSPrimitiveValue::CSS_PC) || value->unit == CSSPrimitiveValue::CSS_REMS) || (value->unit == CSSPrimitiveValue::CSS_NUMBER && !(value->fValue))) || value->fValue < 0)
+    if (!(positiveLengthUnit(value->unit) || (value->unit == CSSPrimitiveValue::CSS_NUMBER && !(value->fValue))) || value->fValue < 0)

[alancutter (OOO until 2018), 2014/07/29 03:25:15]

It's within the style guide to make comparisons with 0.
value->fValue == 0 is probably clearer than !(value->fValue).

         return false;