List message decryption failures on chrome://gcm-internals

components/gcm_driver/crypto/gcm_encryption_provider.h

 // Copyright 2015 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 COMPONENTS_GCM_DRIVER_CRYPTO_GCM_ENCRYPTION_PROVIDER_H_
 #define COMPONENTS_GCM_DRIVER_CRYPTO_GCM_ENCRYPTION_PROVIDER_H_
 
 #include <stdint.h>
 #include <string>
 
@@ skipping 40 matching lines @@
     // The public key provided in the Crypto-Key header is invalid.
     DECRYPTION_FAILURE_INVALID_PUBLIC_KEY,
 
     // The payload could not be decrypted as AES-128-GCM.
     DECRYPTION_FAILURE_INVALID_PAYLOAD
   };
 
   // Callback to be invoked when a message cannot be decoded.
   using DecryptionFailedCallback = base::Callback<void(DecryptionFailure)>;
 
+  // Converts |reason| to a string describing the details of said reason.
+  static std::string ToDecryptionFailureDetailsString(DecryptionFailure reason);
+
   GCMEncryptionProvider();
   ~GCMEncryptionProvider();
 
   // Initializes the encryption provider with the |store_path| and the
   // |blocking_task_runner|. Done separately from the constructor in order to
   // avoid needing a blocking task runner for anything using GCMDriver.
   void Init(
       const base::FilePath& store_path,
       const scoped_refptr<base::SequencedTaskRunner>& blocking_task_runner);
 
@@ skipping 38 matching lines @@
   scoped_ptr<GCMKeyStore> key_store_;
 
   base::WeakPtrFactory<GCMEncryptionProvider> weak_ptr_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(GCMEncryptionProvider);
 };
 
 }  // namespace gcm
 
 #endif  // COMPONENTS_GCM_DRIVER_CRYPTO_GCM_ENCRYPTION_PROVIDER_H_