Remove unused 'Credential::create' methods.

Source/modules/credentialmanager/Credential.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 "modules/credentialmanager/Credential.h"
 
 #include "bindings/core/v8/ExceptionState.h"
 #include "core/dom/ExceptionCode.h"
 
 namespace blink {
 
-Credential* Credential::create(const String& id, const String& name, const KURL& icon)
-{
-    return new Credential(id, name, icon);
-}
-
-Credential* Credential::create(const String& id, const String& name, const String& icon, ExceptionState& exceptionState)
-{
-    KURL iconURL = parseStringAsURL(icon, exceptionState);
-    if (exceptionState.hadException())
-        return nullptr;
-    return new Credential(id, name, iconURL);
-}
-
 Credential::Credential(PlatformCredential* credential)
     : m_platformCredential(credential)
 {
 }
 
 Credential::Credential(const String& id, const String& name, const KURL& icon)
     : m_platformCredential(PlatformCredential::create(id, name, icon))
 {
 }
 
 KURL Credential::parseStringAsURL(const String& url, ExceptionState& exceptionState)
 {
     if (url.isEmpty())
         return KURL();
     KURL parsedURL = KURL(KURL(), url);
     if (!parsedURL.isValid())
         exceptionState.throwDOMException(SyntaxError, "'" + url + "' is not a valid URL.");
     return parsedURL;
 }
 
 DEFINE_TRACE(Credential)
 {
     visitor->trace(m_platformCredential);
 }
 
 } // namespace blink