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

Source/core/css/MediaQueryExp.cpp

 /*
  * CSS Media Query
  *
  * Copyright (C) 2006 Kimmo Kinnunen <kimmo.t.kinnunen@nokia.com>.
  * Copyright (C) 2010 Nokia Corporation and/or its subsidiary(-ies).
  * Copyright (C) 2013 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:
@@ skipping 49 matching lines @@
     if (mediaFeature == pointerMediaFeature)
         return ident == CSSValueNone || ident == CSSValueCoarse || ident == CSSValueFine;
 
     if (mediaFeature == scanMediaFeature)
         return ident == CSSValueInterlace || ident == CSSValueProgressive;
 
     ASSERT_NOT_REACHED();
     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;
 
 
     return mediaFeature == heightMediaFeature
         || mediaFeature == maxHeightMediaFeature
         || mediaFeature == minHeightMediaFeature
         || mediaFeature == widthMediaFeature
         || mediaFeature == maxWidthMediaFeature
         || mediaFeature == minWidthMediaFeature
         || mediaFeature == deviceHeightMediaFeature
@@ skipping 231 matching lines @@
         output.append("/");
         output.append(printNumber(denominator));
     } else if (isID) {
         output.append(getValueName(id));
     }
 
     return output.toString();
 }
 
 } // namespace