Implement FakeAuthPolicyClient::RefreshDevicePolicy()

chromeos/dbus/fake_auth_policy_client.cc

 // Copyright (c) 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.
+
 #include "chromeos/dbus/fake_auth_policy_client.h"
 
+#include "base/bind.h"
+#include "base/files/file_path.h"
+#include "base/files/file_util.h"
+#include "base/location.h"
+#include "base/path_service.h"
+#include "base/task_runner_util.h"
+#include "base/threading/worker_pool.h"
+#include "chrome/browser/chromeos/policy/proto/chrome_device_policy.pb.h"
+#include "chromeos/chromeos_paths.h"
+#include "components/policy/proto/device_management_backend.pb.h"
+
+namespace em = enterprise_management;
+
+namespace {
+
+// Create minimal stub device policy file and drop it at the place where
+// SessionManagerClientStubImpl is looking for it.
+bool WriteDevicePolicyFile() {
+  em::ChromeDeviceSettingsProto policy;
+  em::PolicyData data;
+  policy.SerializeToString(data.mutable_policy_value());
+  data.set_policy_type("google/chromeos/device");
+
+  em::PolicyFetchResponse response;
+  data.SerializeToString(response.mutable_policy_data());
+  std::string serialized_response;
+  response.SerializeToString(&serialized_response);
+
+  base::FilePath owner_key_path;
+  if (!PathService::Get(chromeos::FILE_OWNER_KEY, &owner_key_path))
+    return false;
+
+  const base::FilePath device_policy_path =
+      owner_key_path.DirName().AppendASCII("stub_device_policy");
+
+  // Note that in theory there could be a short time window in which a
+  // concurrent reader sees a partial (and thus invalid) file, but given the
+  // small file size that seems very unlikely in practice.
+  const int bytes_written =
+      base::WriteFile(device_policy_path, serialized_response.c_str(),
+                      serialized_response.size());
+  if (bytes_written < 0)
+    return false;
+  return bytes_written == static_cast<int>(serialized_response.size());

[achuithb, 2016/12/01 20:26:14]

It's a matter of taste, but worth considering combining the two conditions:
return bytes_written > 0 && bytes_written == static_cast<int>(...);

[Thiemo Nagel, 2016/12/01 20:47:21]

I find the way I wrote it much clearer which proves that it's a matter of
personal preference... ;)

+}
+
+}  // namespace
+
 namespace chromeos {
 
 FakeAuthPolicyClient::FakeAuthPolicyClient() {}
 
 FakeAuthPolicyClient::~FakeAuthPolicyClient() {}
 
 void FakeAuthPolicyClient::Init(dbus::Bus* bus) {}
 
 void FakeAuthPolicyClient::JoinAdDomain(const std::string& machine_name,
                                         const std::string& user,
                                         int password_fd,
                                         const JoinCallback& callback) {
   callback.Run(authpolicy::AD_JOIN_ERROR_NONE);
 }
 
 void FakeAuthPolicyClient::RefreshDevicePolicy(
     const RefreshPolicyCallback& callback) {
-  callback.Run(true);
-};
+  if (!base::PostTaskAndReplyWithResult(
+          base::WorkerPool::GetTaskRunner(false /* task_is_slow */).get(),
+          FROM_HERE, base::Bind(&WriteDevicePolicyFile), callback)) {
+    callback.Run(false);
+  }
+}
 
 void FakeAuthPolicyClient::RefreshUserPolicy(
     const std::string& account_id,
     const RefreshPolicyCallback& callback) {
   callback.Run(true);
-};
+}
 
 }  // namespace chromeos