Split Dictionary's get and convert into DictionaryHelper.

Source/core/css/FontFace.cpp

Index: Source/core/css/FontFace.cpp
diff --git a/Source/core/css/FontFace.cpp b/Source/core/css/FontFace.cpp
index cbb007713ef9c224d7c0925a56571101b22ca816..0216bbd80cff6e4d8a895fd69666e45129c9c85f 100644
--- a/Source/core/css/FontFace.cpp
+++ b/Source/core/css/FontFace.cpp
@@ -110,32 +110,32 @@ static bool initFontFace(FontFace* fontFace, ExecutionContext* context, const At
         return false;
 
     String value;
-    if (descriptors.get("style", value)) {
+    if (DictionaryHelper::get(descriptors, "style", value)) {
         fontFace->setStyle(context, value, exceptionState);
         if (exceptionState.hadException())
             return false;
     }
-    if (descriptors.get("weight", value)) {
+    if (DictionaryHelper::get(descriptors, "weight", value)) {
         fontFace->setWeight(context, value, exceptionState);
         if (exceptionState.hadException())
             return false;
     }
-    if (descriptors.get("stretch", value)) {
+    if (DictionaryHelper::get(descriptors, "stretch", value)) {
         fontFace->setStretch(context, value, exceptionState);
         if (exceptionState.hadException())
             return false;
     }
-    if (descriptors.get("unicodeRange", value)) {
+    if (DictionaryHelper::get(descriptors, "unicodeRange", value)) {
         fontFace->setUnicodeRange(context, value, exceptionState);
         if (exceptionState.hadException())
             return false;
     }
-    if (descriptors.get("variant", value)) {
+    if (DictionaryHelper::get(descriptors, "variant", value)) {
         fontFace->setVariant(context, value, exceptionState);
         if (exceptionState.hadException())
             return false;
     }
-    if (descriptors.get("featureSettings", value)) {
+    if (DictionaryHelper::get(descriptors, "featureSettings", value)) {
         fontFace->setFeatureSettings(context, value, exceptionState);
         if (exceptionState.hadException())
             return false;