Handle font-weigths with 'bolder' or 'lighter' values in @font-face rules

Source/core/css/FontFace.cpp

 /*
  * Copyright (C) 2013 Google 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:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 425 matching lines @@
             break;
         case CSSValue500:
             weight = FontWeight500;
             break;
         case CSSValue300:
             weight = FontWeight300;
             break;
         case CSSValue200:
             weight = FontWeight200;
             break;
-        case CSSValueLighter:
         case CSSValue100:
             weight = FontWeight100;
             break;
+        // Although 'lighter' and 'bolder' are valid keywords for font-weights, they are invalid
+        // inside font-face rules so they are ignored. Reference: http://www.w3.org/TR/css3-fonts/#descdef-font-weight.
+        case CSSValueLighter:
+        case CSSValueBolder:
+            break;
         default:
             ASSERT_NOT_REACHED();
             break;
         }
     }
 
     FontVariant variant = FontVariantNormal;
     if (RefPtrWillBeRawPtr<CSSValue> fontVariant = m_variant) {
         // font-variant descriptor can be a value list.
         if (fontVariant->isPrimitiveValue()) {
@@ skipping 130 matching lines @@
     visitor->trace(m_cssFontFace);
     visitor->trace(m_callbacks);
 }
 
 bool FontFace::hadBlankText() const
 {
     return m_cssFontFace->hadBlankText();
 }
 
 } // namespace blink