Initialize OSCrypt with a TaskRunner on the main thread

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"
+#include "base/memory/ref_counted.h"
+#include "base/single_thread_task_runner.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);
 
   // The product name to use for permission prompts.
   static void SetProductName(const std::string& product_name);
 
+  // A runner on the main thread for gnome-keyring to be called from.
+  // TODO(crbug/466975): Libsecret and KWallet don't need this. We can remove
+  // this when we stop supporting keyring.
+  static void SetMainThreadRunner(
+      scoped_refptr<base::SingleThreadTaskRunner> main_thread_runner);
+
   // Tries to load the appropriate key storage. Returns 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;
 
   // The name of the group, if any, containing the key.
   static const char kFolderName[];
   // The name of the entry with the encryption key.
   static const char kKey[];
 
  private:
   DISALLOW_COPY_AND_ASSIGN(KeyStorageLinux);
 };
 
 #endif  // COMPONENTS_OS_CRYPT_KEY_STORAGE_LINUX_H_