Revert of Forward password-store switch to OSCrypt component

components/os_crypt/key_storage_linux.h

 // Copyright 2016 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_OS_CRYPT_KEY_STORAGE_LINUX_H_
 #define COMPONENTS_OS_CRYPT_KEY_STORAGE_LINUX_H_
 
 #include <memory>
 #include <string>
 
 #include "base/macros.h"
 
 // An API for retrieving OSCrypt's password from the system's password storage
 // service.
 class KeyStorageLinux {
  public:
   KeyStorageLinux() = default;
   virtual ~KeyStorageLinux() = default;
 
-  // Force OSCrypt to use a specific linux password store.
-  static void SetStore(const std::string& store_type);
-
-  // Tries to load the appropriate key storage. Returns null if none succeed.
+  // Tries to load all known key storages. Returns the first that succeeds or
+  // null if none succeed.
   static std::unique_ptr<KeyStorageLinux> CreateService();
 
   // Gets the encryption key from the OS password-managing library. If a key is
   // not found, a new key will be generated, stored and returned.
   virtual std::string GetKey() = 0;
 
  protected:
   // Loads the key storage. Returns false if the service is not available.
   virtual bool Init() = 0;
 
  private:
   DISALLOW_COPY_AND_ASSIGN(KeyStorageLinux);
 };
 
 #endif  // COMPONENTS_OS_CRYPT_KEY_STORAGE_LINUX_H_