Remove the notifyFailedSignedIn callback from Blink.

Source/modules/credentialmanager/CredentialsContainer.h

 // 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.
 
 #ifndef CredentialsContainer_h
 #define CredentialsContainer_h
 
 #include "bindings/core/v8/ScriptWrappable.h"
 #include "platform/heap/Handle.h"
 
 namespace blink {
 
 class Credential;
 class CredentialRequestOptions;
 class Dictionary;
 class ScriptPromise;
 class ScriptState;
 
 class CredentialsContainer final : public GarbageCollected<CredentialsContainer>, public ScriptWrappable {
     DEFINE_WRAPPERTYPEINFO();
 public:
     static CredentialsContainer* create();
 
     // CredentialsContainer.h
     ScriptPromise request(ScriptState*, const CredentialRequestOptions&);
     ScriptPromise notifySignedIn(ScriptState*, Credential* = 0);
-    ScriptPromise notifyFailedSignIn(ScriptState*, Credential* = 0);
     ScriptPromise requireUserMediation(ScriptState*);
 
     DEFINE_INLINE_VIRTUAL_TRACE() { }
 
 private:
     CredentialsContainer();
 };
 
 } // namespace blink
 
 #endif // CredentialsContainer_h