Revert "[OSCrypt][Password Manager] Introduce TaskRunner for libsecret"

This reverts commit a22b9873.

Reason for revert: Password Manager initialisation depends on oscrypt,
which creates the possibility of deadlock. See crbug/795019

Original change's description:
> [OSCrypt][Password Manager] Introduce TaskRunner for libsecret
> 
> A SequencedTaskRunner will be used to guarantee no race conditions
> between the two clients of libsecret.
> 
> Bug: 782851
> Change-Id: I6549f867a14378d019404429bab42008fca548a7
> Reviewed-on: https://chromium-review.googlesource.com/803954
> Commit-Queue: Christos Froussios <cfroussios@chromium.org>
> Reviewed-by: Vaclav Brozek <vabr@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#523409}

TBR=vabr@chromium.org,cfroussios@chromium.org

# Not skipping CQ checks because original CL landed > 1 day ago.

Bug: 782851,795019
Change-Id: Ie435a623de544767189571b80f929777af881012
Reviewed-on: https://chromium-review.googlesource.com/826070Reviewed-by: Christos Froussios <cfroussios@chromium.org>
Commit-Queue: Christos Froussios <cfroussios@chromium.org>
Cr-Commit-Position: refs/heads/master@{#524178}

chrome/browser/password_manager/native_backend_libsecret.cc

@@ -20,7 +20,6 @@
 #include "base/strings/string_number_conversions.h"
 #include "base/strings/stringprintf.h"
 #include "base/strings/utf_string_conversions.h"
-#include "components/os_crypt/libsecret_task_runner_linux.h"
 #include "components/password_manager/core/browser/password_manager_metrics_util.h"
 #include "components/password_manager/core/browser/password_manager_util.h"
 #include "url/origin.h"
@@ -413,7 +412,7 @@ bool NativeBackendLibsecret::GetAllLogins(
 
 scoped_refptr<base::SequencedTaskRunner>
 NativeBackendLibsecret::GetBackgroundTaskRunner() {
-  return os_crypt::GetLibsecretTaskRunner();
+  return nullptr;
 }
 
 bool NativeBackendLibsecret::GetLoginsList(

components/os_crypt/BUILD.gn

@@ -97,8 +97,6 @@ static_library("os_crypt") {
       sources += [
         "key_storage_libsecret.cc",
         "key_storage_libsecret.h",
-        "libsecret_task_runner_linux.cc",
-        "libsecret_task_runner_linux.h",
         "libsecret_util_linux.cc",
         "libsecret_util_linux.h",
       ]

components/os_crypt/key_storage_libsecret.cc

@@ -6,9 +6,7 @@
 
 #include "base/base64.h"
 #include "base/rand_util.h"
-#include "base/sequenced_task_runner.h"
 #include "base/strings/string_number_conversions.h"
-#include "components/os_crypt/libsecret_task_runner_linux.h"
 #include "components/os_crypt/libsecret_util_linux.h"
 
 namespace {
@@ -53,10 +51,6 @@ SecretValue* ToSingleSecret(GList* secret_items) {
 
 }  // namespace
 
-base::SequencedTaskRunner* KeyStorageLibsecret::GetTaskRunner() {
-  return os_crypt::GetLibsecretTaskRunner().get();
-}
-
 std::string KeyStorageLibsecret::AddRandomPasswordInLibsecret() {
   std::string password;
   base::Base64Encode(base::RandBytesAsString(16), &password);

components/os_crypt/key_storage_libsecret.h

@@ -10,10 +10,6 @@
 #include "base/macros.h"
 #include "components/os_crypt/key_storage_linux.h"
 
-namespace base {
-class SequencedTaskRunner;
-}
-
 // Specialisation of KeyStorageLinux that uses Libsecret.
 class KeyStorageLibsecret : public KeyStorageLinux {
  public:
@@ -22,7 +18,6 @@ class KeyStorageLibsecret : public KeyStorageLinux {
 
  protected:
   // KeyStorageLinux
-  base::SequencedTaskRunner* GetTaskRunner() override;
   bool Init() override;
   std::string GetKeyImpl() override;
 

components/os_crypt/key_storage_libsecret_unittest.cc

@@ -6,7 +6,6 @@
 
 #include "base/logging.h"
 #include "base/macros.h"
-#include "base/test/scoped_task_environment.h"
 #include "components/os_crypt/key_storage_libsecret.h"
 #include "components/os_crypt/libsecret_util_linux.h"
 #include "testing/gtest/include/gtest/gtest.h"
@@ -216,8 +215,6 @@ class LibsecretTest : public testing::Test {
   void TearDown() override { MockLibsecretLoader::TearDown(); }
 
  private:
-  base::test::ScopedTaskEnvironment scoped_task_environment_;
-
   DISALLOW_COPY_AND_ASSIGN(LibsecretTest);
 };
 

components/os_crypt/libsecret_task_runner_linux.cc

-// Copyright 2017 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.
-
-#include "components/os_crypt/libsecret_task_runner_linux.h"
-
-#include "base/task_scheduler/lazy_task_runner.h"
-
-namespace os_crypt {
-
-namespace {
-
-// Use TaskPriority::USER_BLOCKING, because profile initialisation may block on
-// initialising OSCrypt, which in turn may contact libsecret.
-base::LazySingleThreadTaskRunner g_libsecret_thread_task_runner =
-    LAZY_SINGLE_THREAD_TASK_RUNNER_INITIALIZER(
-        base::TaskTraits(base::MayBlock(), base::TaskPriority::USER_BLOCKING),
-        base::SingleThreadTaskRunnerThreadMode::SHARED);
-
-}  // namespace
-
-// TODO(crbug.com/571003) Remove this if OSCrypt is the only client of keyring.
-scoped_refptr<base::SequencedTaskRunner> GetLibsecretTaskRunner() {
-  return g_libsecret_thread_task_runner.Get();
-}
-
-}  // namespace os_crypt

components/os_crypt/libsecret_task_runner_linux.h

-// Copyright 2017 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_LIBSECRET_TASK_RUNNER_LINUX_H_
-#define COMPONENTS_OS_CRYPT_LIBSECRET_TASK_RUNNER_LINUX_H_
-
-#include "base/memory/ref_counted.h"
-#include "base/sequenced_task_runner.h"
-
-// Concurrent calls to the libsecret library may sometimes cause erroneous
-// behaviour. Use this TaskRunner to remove race conditions between all
-// components interacting with libsecret.
-
-namespace os_crypt {
-
-scoped_refptr<base::SequencedTaskRunner> GetLibsecretTaskRunner();
-
-}  // namespace os_crypt
-
-#endif  // COMPONENTS_OS_CRYPT_LIBSECRET_TASK_RUNNER_LINUX_H_