Fix race issue in ArcAuthService.

chrome/browser/chromeos/arc/auth/arc_manual_auth_code_fetcher.cc

+// 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.
+
+#include "chrome/browser/chromeos/arc/auth/arc_manual_auth_code_fetcher.h"
+
+#include "base/bind.h"
+#include "base/callback_helpers.h"
+#include "base/logging.h"
+#include "chrome/browser/chromeos/arc/arc_auth_context.h"
+
+namespace arc {
+
+ArcManualAuthCodeFetcher::ArcManualAuthCodeFetcher(ArcAuthContext* context,
+                                                   ArcSupportHost* support_host)
+    : context_(context), support_host_(support_host), weak_ptr_factory_(this) {
+  DCHECK(context_);
+  DCHECK(support_host_);
+  support_host_->AddObserver(this);
+}
+
+ArcManualAuthCodeFetcher::~ArcManualAuthCodeFetcher() {
+  support_host_->RemoveObserver(this);
+}
+
+void ArcManualAuthCodeFetcher::Fetch(const FetchCallback& callback) {
+  DCHECK(pending_callback_.is_null());
+  pending_callback_ = callback;
+
+  FetchInternal();
+}
+
+void ArcManualAuthCodeFetcher::FetchInternal() {
+  DCHECK(!pending_callback_.is_null());
+  context_->Prepare(base::Bind(&ArcManualAuthCodeFetcher::OnContextPrepared,
+                               weak_ptr_factory_.GetWeakPtr()));
+}
+
+void ArcManualAuthCodeFetcher::OnContextPrepared(
+    net::URLRequestContextGetter* request_context_getter) {
+  DCHECK(!pending_callback_.is_null());
+  if (!request_context_getter) {
+    support_host_->ShowError(ArcSupportHost::Error::SIGN_IN_NETWORK_ERROR,
+                             false);
+    return;
+  }
+
+  support_host_->ShowLso();
+}
+
+void ArcManualAuthCodeFetcher::OnAuthSucceeded(const std::string& auth_code) {
+  DCHECK(!pending_callback_.is_null());
+  base::ResetAndReturn(&pending_callback_).Run(auth_code);
+}
+
+void ArcManualAuthCodeFetcher::OnRetryClicked() {
+  DCHECK(!pending_callback_.is_null());
+  FetchInternal();
+}
+
+}  // namespace arc