Split Dictionary's get and convert into DictionaryHelper.

Source/modules/serviceworkers/ResponseInit.h

Index: Source/modules/serviceworkers/ResponseInit.h
diff --git a/Source/modules/serviceworkers/ResponseInit.h b/Source/modules/serviceworkers/ResponseInit.h
index bda31bd5aa5efa060d908307e065a9ca6b326fbe..221f7a215c623b7220bbfe824d5b0bebd4f220f6 100644
--- a/Source/modules/serviceworkers/ResponseInit.h
+++ b/Source/modules/serviceworkers/ResponseInit.h
@@ -6,6 +6,7 @@
 #define ResponseInit_h
 
 #include "bindings/core/v8/Dictionary.h"
+#include "bindings/core/v8/DictionaryHelper.h"
 #include "modules/serviceworkers/HeaderMap.h"
 #include "wtf/RefPtr.h"
 
@@ -21,10 +22,10 @@ struct ResponseInit {
         : status(200)
         , statusText("OK")
     {
-        options.get("status", status);
+        DictionaryHelper::get(options, "status", status);
         // FIXME: Spec uses ByteString for statusText. http://crbug.com/347426
-        options.get("statusText", statusText);
-        options.get("headers", headers);
+        DictionaryHelper::get(options, "statusText", statusText);
+        DictionaryHelper::get(options, "headers", headers);
     }
 
     unsigned short status;