Add ForceSigninVerifier.

chrome/browser/signin/force_signin_verifier.cc

Index: chrome/browser/signin/force_signin_verifier.cc
diff --git a/chrome/browser/signin/force_signin_verifier.cc b/chrome/browser/signin/force_signin_verifier.cc
new file mode 100644
index 0000000000000000000000000000000000000000..6bf03ba72c7232a6d7c0e798b3e9bf434b0f8212
--- /dev/null
+++ b/chrome/browser/signin/force_signin_verifier.cc
@@ -0,0 +1,107 @@
+// 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 <string>
+
+#include "chrome/browser/profiles/profile.h"
+#include "chrome/browser/signin/force_signin_verifier.h"
+#include "chrome/browser/signin/profile_oauth2_token_service_factory.h"
+#include "chrome/browser/signin/signin_manager_factory.h"
+#include "components/signin/core/browser/signin_manager.h"
+#include "google_apis/gaia/gaia_constants.h"
+
+namespace {
+const net::BackoffEntry::Policy kBackoffPolicy = {
+    0,              // Number of initial errors to ignore before applying
+                    // exponential back-off rules.
+    2000,           // Initial delay in ms.
+    2,              // Factor by which the waiting time will be multiplied.
+    0.2,            // Fuzzing percentage.
+    4 * 60 * 1000,  // Maximum amount of time to delay th request in ms.
+    -1,             // Never discard the entry.
+    false           // Do not always use initial delay.
+};
+
+}  // namespace
+
+ForceSigninVerifier::ForceSigninVerifier(Profile* profile)
+    : OAuth2TokenService::Consumer("force_signin_verifier"),
+      has_token_verified_(false),
+      backoff_entry_(&kBackoffPolicy),
+      token_request_time_(base::Time::Now()),
+      oauth2_token_service_(
+          ProfileOAuth2TokenServiceFactory::GetForProfile(profile)),
+      signin_manager_(SigninManagerFactory::GetForProfile(profile)) {
+  net::NetworkChangeNotifier::AddNetworkChangeObserver(this);
+  SendRequest();
+}
+
+ForceSigninVerifier::~ForceSigninVerifier() {
+  Cancel();
+}
+
+bool ForceSigninVerifier::ShouldSendRequest() {
+  return !has_token_verified_ && access_token_request_.get() == nullptr &&
+         !net::NetworkChangeNotifier::IsOffline() &&
+         signin_manager_->IsAuthenticated();
+}
+
+void ForceSigninVerifier::SendRequest() {
+  if (!ShouldSendRequest())
+    return;
+
+  std::string account_id = signin_manager_->GetAuthenticatedAccountId();
+  OAuth2TokenService::ScopeSet oauth2_scopes;
+  oauth2_scopes.insert(GaiaConstants::kChromeSyncOAuth2Scope);
+  access_token_request_ =
+      oauth2_token_service_->StartRequest(account_id, oauth2_scopes, this);
+}
+
+void ForceSigninVerifier::OnGetTokenSuccess(
+    const OAuth2TokenService::Request* request,
+    const std::string& access_token,
+    const base::Time& expiration_time) {
+  has_token_verified_ = true;
+  net::NetworkChangeNotifier::RemoveNetworkChangeObserver(this);
+  access_token_request_.reset();

[Roger Tawa OOO till Jul 10th, 2017/04/10 15:15:20]

Would it be better to call Cancel() instead of lines 66-67?
Same for line 76.

[zmin, 2017/04/10 22:27:49]

Done.

+}
+
+void ForceSigninVerifier::OnGetTokenFailure(
+    const OAuth2TokenService::Request* request,
+    const GoogleServiceAuthError& error) {
+  if (error.IsPersistentError()) {
+    has_token_verified_ = true;
+    ShowDialog();
+    net::NetworkChangeNotifier::RemoveNetworkChangeObserver(this);
+  } else {
+    backoff_entry_.InformOfRequest(false);
+    backoff_request_timer_.Start(
+        FROM_HERE, backoff_entry_.GetTimeUntilRelease(),
+        base::Bind(&ForceSigninVerifier::SendRequest, base::Unretained(this)));
+  }
+  access_token_request_.reset();
+}
+
+void ForceSigninVerifier::OnNetworkChanged(
+    net::NetworkChangeNotifier::ConnectionType type) {
+  // Try again immediately once the network is back and cancel any pending
+  // request.
+  backoff_entry_.Reset();
+  if (backoff_request_timer_.IsRunning())
+    backoff_request_timer_.Stop();
+
+  if (type != net::NetworkChangeNotifier::ConnectionType::CONNECTION_NONE)
+    SendRequest();
+}
+
+void ForceSigninVerifier::Cancel() {
+  backoff_entry_.Reset();
+  backoff_request_timer_.Stop();
+  access_token_request_.reset();
+  net::NetworkChangeNotifier::RemoveNetworkChangeObserver(this);
+}
+
+void ForceSigninVerifier::ShowDialog() {
+  // TODO(zmin): Show app modal dialog.
+}