Add parseFontFaceDescriptor for @font-face handling

Source/core/css/parser/CSSParser.cpp

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "config.h"
 #include "core/css/parser/CSSParser.h"
 
 #include "core/css/CSSKeyframeRule.h"
 #include "core/css/StyleColor.h"
 #include "core/css/StyleRule.h"
@@ skipping 158 matching lines @@
     cssColor.init(colorString);
     CSSValueID id = cssValueKeywordID(cssColor);
     if (!CSSPropertyParser::isSystemColor(id))
         return false;
 
     Color parsedColor = LayoutTheme::theme().systemColor(id);
     color = parsedColor.rgb();
     return true;
 }
 
+PassRefPtrWillBeRawPtr<CSSValue> CSSParser::parseFontFaceDescriptor(CSSPropertyID propertyID, const String& propertyValue, const CSSParserContext& context)
+{
+    StringBuilder builder;
+    builder.appendLiteral("@font-face { ");
+    builder.append(getPropertyNameString(propertyID));
+    builder.appendLiteral(" : ");
+    builder.append(propertyValue);
+    builder.appendLiteral("; }");
+    RefPtrWillBeRawPtr<StyleRuleBase> rule = parseRule(context, 0, builder.toString());
+    if (!rule || !rule->isFontFaceRule())
+        return nullptr;
+    return toStyleRuleFontFace(rule.get())->properties().getPropertyCSSValue(propertyID);
+}
+
 } // namespace blink