Revert of Hook up the Push API with GCM's new ability to own encryption keys.

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>
-
-#include "base/callback_forward.h"
-#include "base/macros.h"
-#include "base/memory/ref_counted.h"
-#include "base/memory/weak_ptr.h"
-
-namespace base {
-class FilePath;
-class SequencedTaskRunner;
-}
-
-namespace gcm {
-
-class GCMKeyStore;
-class KeyPair;
-
-// Provider that enables the GCM Driver to deal with encryption key management
-// and decryption of incoming messages.
-class GCMEncryptionProvider {
- public:
-  // Callback to be invoked when the public encryption key is available.
-  using PublicKeyCallback = base::Callback<void(const std::string&)>;
-
-  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);
-
-  // Retrieves the public encryption key belonging to |app_id|. If no keys have
-  // been associated with |app_id| yet, they will be created.
-  void GetPublicKey(const std::string& app_id,
-                    const PublicKeyCallback& callback);
-
- private:
-  void DidGetPublicKey(const std::string& app_id,
-                       const PublicKeyCallback& callback,
-                       const KeyPair& pair);
-
-  void DidCreatePublicKey(const PublicKeyCallback& callback,
-                          const KeyPair& pair);
-
-  scoped_refptr<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_