Added interstitial page for merge session. This page will let us delay loading of Google properties during ChromeOS cookie session restore at login (aka /MergeSession).

The interstitial page will show 3 seconds of no UI (white tab) followed with up to 7 seconds of UI with only "Loading..." message showing in tabs. For huge majority of cases, that secondary UI won't show since merge session will probably complete by then.

BUG=171980
TEST=added merge_session_load_page_unittest.cc
TBR=sky

Review URL: https://codereview.chromium.org/12256046

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@182894 0039d316-1c4b-4281-b951-d872f2087c98

17 files changed, 653 insertions, 6 deletions

diff --git a/chrome/browser/browser_resources.grd b/chrome/browser/browser_resources.grd
index b364ba3..5450283 100644
--- a/chrome/browser/browser_resources.grd
+++ b/chrome/browser/browser_resources.grd
@@ -283,6 +283,7 @@
         <include name="IDR_NOTIFICATION_ICON_LINK_HTML" file="resources\chromeos\notification_icon_link.html" type="BINDATA" />
         <include name="IDR_ECHO_MANIFEST" file="resources\chromeos\echo\manifest.json" type="BINDATA" />
         <include name="IDR_OFFLINE_LOAD_HTML" file="resources\chromeos\offline_load.html" flattenhtml="true" type="BINDATA" />
+        <include name="IDR_MERGE_SESSION_LOAD_HTML" file="resources\chromeos\merge_session_load.html" flattenhtml="true" type="BINDATA" />
         <include name="IDR_OS_CREDITS_HTML" file="resources\chromeos\about_os_credits.html" flattenhtml="true" type="BINDATA" />
         <include name="IDR_PROXY_SETTINGS_HTML" file="resources\chromeos\proxy_settings.html" flattenhtml="true" type="BINDATA" />
         <include name="IDR_BLUETOOTH_PAIR_DEVICE_HTML" file="resources\chromeos\bluetooth_pair_device.html" flattenhtml="true" type="BINDATA" />
diff --git a/chrome/browser/chromeos/login/login_utils.cc b/chrome/browser/chromeos/login/login_utils.cc
index e1874f9..482174c 100644
--- a/chrome/browser/chromeos/login/login_utils.cc
+++ b/chrome/browser/chromeos/login/login_utils.cc
@@ -229,6 +229,7 @@ class LoginUtilsImpl
   virtual void InitRlzDelayed(Profile* user_profile) OVERRIDE;
 
   // OAuthLoginManager::Delegate overrides.
+  virtual void OnCompletedMergeSession() OVERRIDE;
   virtual void OnCompletedAuthentication(Profile* user_profile) OVERRIDE;
   virtual void OnFoundStoredTokens() OVERRIDE;
 
@@ -561,6 +562,8 @@ void LoginUtilsImpl::RestoreAuthSession(Profile* user_profile,
   if (!login_manager_.get())
     return;
 
+  UserManager::Get()->SetMergeSessionState(
+      UserManager::MERGE_STATUS_IN_PROCESS);
   // Remove legacy OAuth1 token if we have one. If it's valid, we should already
   // have OAuth2 refresh token in TokenService that could be used to retrieve
   // all other tokens and credentials.
@@ -997,6 +1000,10 @@ void LoginUtilsImpl::OnCompletedAuthentication(Profile* user_profile) {
   StartSignedInServices(user_profile);
 }
 
+void LoginUtilsImpl::OnCompletedMergeSession() {
+  UserManager::Get()->SetMergeSessionState(UserManager::MERGE_STATUS_DONE);
+}
+
 void LoginUtilsImpl::OnFoundStoredTokens() {
   // We don't need authenticator instance any more since its cookie jar
   // is not going to needed to mint OAuth tokens. Reset it so that
diff --git a/chrome/browser/chromeos/login/merge_session_load_page.cc b/chrome/browser/chromeos/login/merge_session_load_page.cc
new file mode 100644
index 0000000..c1c8c60
--- /dev/null
+++ b/chrome/browser/chromeos/login/merge_session_load_page.cc
@@ -0,0 +1,150 @@
+// Copyright (c) 2013 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/login/merge_session_load_page.h"
+
+#include "ash/shell.h"
+#include "ash/shell_delegate.h"
+#include "ash/system/tray/system_tray_delegate.h"
+#include "base/i18n/rtl.h"
+#include "base/metrics/histogram.h"
+#include "base/string_piece.h"
+#include "base/stringprintf.h"
+#include "base/utf_string_conversions.h"
+#include "base/values.h"
+#include "chrome/browser/chromeos/cros/cros_library.h"
+#include "chrome/browser/chromeos/cros/network_library.h"
+#include "chrome/browser/extensions/extension_service.h"
+#include "chrome/browser/extensions/extension_system.h"
+#include "chrome/browser/profiles/profile.h"
+#include "chrome/browser/renderer_preferences_util.h"
+#include "chrome/browser/tab_contents/tab_util.h"
+#include "chrome/common/chrome_notification_types.h"
+#include "chrome/common/extensions/extension.h"
+#include "chrome/common/extensions/extension_constants.h"
+#include "chrome/common/extensions/extension_icon_set.h"
+#include "chrome/common/url_constants.h"
+#include "content/public/browser/browser_thread.h"
+#include "content/public/browser/interstitial_page.h"
+#include "content/public/browser/notification_types.h"
+#include "content/public/browser/web_contents.h"
+#include "grit/browser_resources.h"
+#include "grit/generated_resources.h"
+#include "net/base/escape.h"
+#include "ui/base/l10n/l10n_util.h"
+#include "ui/base/resource/resource_bundle.h"
+#include "ui/webui/jstemplate_builder.h"
+
+using content::BrowserThread;
+using content::InterstitialPage;
+using content::WebContents;
+
+namespace {
+
+// Delay time for showing interstitial page.
+const int kShowDelayTimeMS = 1000;
+
+// Maximum time for showing interstitial page.
+const int kTotalWaitTimeMS = 10000;
+
+}  // namespace
+
+namespace chromeos {
+
+MergeSessionLoadPage::MergeSessionLoadPage(WebContents* web_contents,
+                                           const GURL& url,
+                                           const CompletionCallback& callback)
+    : callback_(callback),
+      proceeded_(false),
+      web_contents_(web_contents),
+      url_(url) {
+  UserManager::Get()->AddObserver(this);
+  interstitial_page_ = InterstitialPage::Create(web_contents, true, url, this);
+}
+
+MergeSessionLoadPage::~MergeSessionLoadPage() {
+  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
+  UserManager::Get()->RemoveObserver(this);
+}
+
+void MergeSessionLoadPage::Show() {
+  interstitial_page_->Show();
+}
+
+std::string MergeSessionLoadPage::GetHTMLContents() {
+  DictionaryValue strings;
+  strings.SetString("title", web_contents_->GetTitle());
+  // Set the timeout to show the page.
+  strings.SetInteger("show_delay_time", kShowDelayTimeMS);
+  strings.SetInteger("total_wait_time", kTotalWaitTimeMS);
+  // TODO(zelidrag): Flip the message to IDS_MERGE_SESSION_LOAD_HEADLINE
+  // after merge.
+  strings.SetString("heading",
+                    l10n_util::GetStringUTF16(IDS_TAB_LOADING_TITLE));
+
+  bool rtl = base::i18n::IsRTL();
+  strings.SetString("textdirection", rtl ? "rtl" : "ltr");
+
+  base::StringPiece html(
+      ResourceBundle::GetSharedInstance().GetRawDataResource(
+          IDR_MERGE_SESSION_LOAD_HTML));
+  return webui::GetI18nTemplateHtml(html, &strings);
+}
+
+void MergeSessionLoadPage::OverrideRendererPrefs(
+      content::RendererPreferences* prefs) {
+  Profile* profile = Profile::FromBrowserContext(
+      web_contents_->GetBrowserContext());
+  renderer_preferences_util::UpdateFromSystemSettings(prefs, profile);
+}
+
+void MergeSessionLoadPage::OnProceed() {
+  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
+  proceeded_ = true;
+  NotifyBlockingPageComplete();
+}
+
+void MergeSessionLoadPage::OnDontProceed() {
+  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
+  // Ignore if it's already proceeded.
+  if (proceeded_)
+    return;
+  NotifyBlockingPageComplete();
+}
+
+void MergeSessionLoadPage::CommandReceived(const std::string& cmd) {
+  std::string command(cmd);
+  // The Jasonified response has quotes, remove them.
+  if (command.length() > 1 && command[0] == '"')
+    command = command.substr(1, command.length() - 2);
+
+  if (command == "proceed") {
+    interstitial_page_->Proceed();
+  } else {
+    DVLOG(1) << "Unknown command:" << cmd;
+  }
+}
+
+void MergeSessionLoadPage::NotifyBlockingPageComplete() {
+  if (!callback_.is_null()) {
+    BrowserThread::PostTask(
+        BrowserThread::IO, FROM_HERE, callback_);
+  }
+}
+
+void MergeSessionLoadPage::MergeSessionStateChanged(
+    UserManager::MergeSessionState state) {
+  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
+  DVLOG(1) << "Merge session is "
+           << (state !=  UserManager:: MERGE_STATUS_IN_PROCESS ?
+                  " NOT " : "")
+           << " in progress, "
+           << state;
+  if (state !=  UserManager:: MERGE_STATUS_IN_PROCESS) {
+    UserManager::Get()->RemoveObserver(this);
+    interstitial_page_->Proceed();
+  }
+}
+
+}  // namespace chromeos
diff --git a/chrome/browser/chromeos/login/merge_session_load_page.h b/chrome/browser/chromeos/login/merge_session_load_page.h
new file mode 100644
index 0000000..39fba94
--- /dev/null
+++ b/chrome/browser/chromeos/login/merge_session_load_page.h
@@ -0,0 +1,86 @@
+// Copyright (c) 2013 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 CHROME_BROWSER_CHROMEOS_LOGIN_MERGE_SESSION_LOAD_PAGE_H_
+#define CHROME_BROWSER_CHROMEOS_LOGIN_MERGE_SESSION_LOAD_PAGE_H_
+
+#include <string>
+
+#include "base/callback.h"
+#include "base/compiler_specific.h"
+#include "chrome/browser/chromeos/login/user_manager.h"
+#include "content/public/browser/interstitial_page_delegate.h"
+#include "googleurl/src/gurl.h"
+
+namespace base {
+class DictionaryValue;
+}
+
+namespace content {
+class InterstitialPage;
+class WebContents;
+}
+
+namespace extensions {
+class Extension;
+}
+
+namespace chromeos {
+
+// MergeSessionLoadPage class shows the interstitial page that is shown
+// while we are trying to restore session containing tabs with Google properties
+// during the process of exchanging OAuth2 refresh token for user cookies.
+// It deletes itself when the interstitial page is closed.
+class MergeSessionLoadPage
+    : public content::InterstitialPageDelegate,
+      public UserManager::Observer {
+ public:
+  // Passed a boolean indicating whether or not it is OK to proceed with the
+  // page load.
+  typedef base::Closure CompletionCallback;
+
+  // Create a merge session load delay page for the |web_contents|.
+  // The |callback| will be run on the IO thread.
+  MergeSessionLoadPage(content::WebContents* web_contents,
+                       const GURL& url,
+                       const CompletionCallback& callback);
+
+  void Show();
+
+ protected:
+  virtual ~MergeSessionLoadPage();
+
+ private:
+  friend class TestMergeSessionLoadPage;
+
+  // InterstitialPageDelegate implementation.
+  virtual std::string GetHTMLContents() OVERRIDE;
+  virtual void CommandReceived(const std::string& command) OVERRIDE;
+  virtual void OverrideRendererPrefs(
+      content::RendererPreferences* prefs) OVERRIDE;
+  virtual void OnProceed() OVERRIDE;
+  virtual void OnDontProceed() OVERRIDE;
+
+  // UserManager::Observer overrides.
+  virtual void MergeSessionStateChanged(
+      UserManager::MergeSessionState state) OVERRIDE;
+  virtual void LocalStateChanged(UserManager* user_manager) OVERRIDE {}
+
+  void NotifyBlockingPageComplete();
+
+  CompletionCallback callback_;
+
+  // True if the proceed is chosen.
+  bool proceeded_;
+
+  content::WebContents* web_contents_;
+  GURL url_;
+  content::InterstitialPage* interstitial_page_;  // Owns us.
+
+  DISALLOW_COPY_AND_ASSIGN(MergeSessionLoadPage);
+};
+
+}  // namespace chromeos
+
+#endif  // CHROME_BROWSER_CHROMEOS_LOGIN_MERGE_SESSION_LOAD_PAGE_H_
diff --git a/chrome/browser/chromeos/login/merge_session_load_page_unittest.cc b/chrome/browser/chromeos/login/merge_session_load_page_unittest.cc
new file mode 100644
index 0000000..c9c7225
--- /dev/null
+++ b/chrome/browser/chromeos/login/merge_session_load_page_unittest.cc
@@ -0,0 +1,127 @@
+// Copyright (c) 2013 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/cros/cros_library.h"
+#include "chrome/browser/chromeos/login/merge_session_load_page.h"
+#include "chrome/test/base/chrome_render_view_host_test_harness.h"
+#include "content/public/browser/interstitial_page.h"
+#include "content/public/browser/navigation_controller.h"
+#include "content/public/browser/web_contents.h"
+#include "content/public/test/test_browser_thread.h"
+#include "content/public/test/web_contents_tester.h"
+
+using content::BrowserThread;
+using content::InterstitialPage;
+using content::WebContents;
+using content::WebContentsTester;
+
+namespace {
+
+const char kURL1[] = "http://www.google.com/";
+const char kURL2[] = "http://mail.google.com/";
+
+}  // namespace
+
+namespace chromeos {
+
+class MergeSessionLoadPageTest;
+
+// An MergeSessionLoadPage class that does not create windows.
+class TestMergeSessionLoadPage :  public MergeSessionLoadPage {
+ public:
+  TestMergeSessionLoadPage(WebContents* web_contents,
+                           const GURL& url,
+                           MergeSessionLoadPageTest* test_page)
+    : MergeSessionLoadPage(web_contents, url, CompletionCallback()),
+      test_page_(test_page) {
+    interstitial_page_->DontCreateViewForTesting();
+  }
+
+ private:
+  MergeSessionLoadPageTest* test_page_;
+
+  DISALLOW_COPY_AND_ASSIGN(TestMergeSessionLoadPage);
+};
+
+class MergeSessionLoadPageTest : public ChromeRenderViewHostTestHarness {
+ public:
+  MergeSessionLoadPageTest()
+      : ui_thread_(BrowserThread::UI, MessageLoop::current()),
+        file_user_blocking_thread_(
+            BrowserThread::FILE_USER_BLOCKING, MessageLoop::current()),
+        io_thread_(BrowserThread::IO, MessageLoop::current()) {
+  }
+
+  void Navigate(const char* url, int page_id) {
+    WebContentsTester::For(web_contents())->TestDidNavigate(
+        web_contents()->GetRenderViewHost(), page_id, GURL(url),
+        content::PAGE_TRANSITION_TYPED);
+  }
+
+  void ShowInterstitial(const char* url) {
+    (new TestMergeSessionLoadPage(web_contents(), GURL(url), this))->Show();
+  }
+
+  // Returns the MergeSessionLoadPage currently showing or NULL if none is
+  // showing.
+  InterstitialPage* GetMergeSessionLoadPage() {
+    return InterstitialPage::GetInterstitialPage(web_contents());
+  }
+
+ private:
+  content::TestBrowserThread ui_thread_;
+  content::TestBrowserThread file_user_blocking_thread_;
+  content::TestBrowserThread io_thread_;
+
+  // Initializes / shuts down a stub CrosLibrary.
+  chromeos::ScopedStubCrosEnabler stub_cros_enabler_;
+
+  DISALLOW_COPY_AND_ASSIGN(MergeSessionLoadPageTest);
+};
+
+TEST_F(MergeSessionLoadPageTest, MergeSessionPageNotShown) {
+  UserManager::Get()->SetMergeSessionState(
+      UserManager::MERGE_STATUS_DONE);
+  // Start a load.
+  Navigate(kURL1, 1);
+  // Load next page.
+  controller().LoadURL(GURL(kURL2), content::Referrer(),
+                       content::PAGE_TRANSITION_TYPED, std::string());
+
+  // Simulate the load causing an merge session interstitial page
+  // to be shown.
+  InterstitialPage* interstitial = GetMergeSessionLoadPage();
+  EXPECT_FALSE(interstitial);
+}
+
+TEST_F(MergeSessionLoadPageTest, MergeSessionPageShown) {
+  UserManager::Get()->SetMergeSessionState(
+      UserManager::MERGE_STATUS_IN_PROCESS);
+  // Start a load.
+  Navigate(kURL1, 1);
+  // Load next page.
+  controller().LoadURL(GURL(kURL2), content::Referrer(),
+                       content::PAGE_TRANSITION_TYPED, std::string());
+
+  // Simulate the load causing an merge session interstitial page
+  // to be shown.
+  ShowInterstitial(kURL2);
+  InterstitialPage* interstitial = GetMergeSessionLoadPage();
+  ASSERT_TRUE(interstitial);
+  MessageLoop::current()->RunUntilIdle();
+
+  // Simulate merge session completion.
+  UserManager::Get()->SetMergeSessionState(
+      UserManager::MERGE_STATUS_DONE);
+  MessageLoop::current()->RunUntilIdle();
+
+  // The URL remains to be URL2.
+  EXPECT_EQ(kURL2, web_contents()->GetURL().spec());
+
+  // Commit navigation and the interstitial page is gone.
+  Navigate(kURL2, 2);
+  EXPECT_FALSE(GetMergeSessionLoadPage());
+}
+
+}  // namespace chromeos
diff --git a/chrome/browser/chromeos/login/merge_session_throttle.cc b/chrome/browser/chromeos/login/merge_session_throttle.cc
new file mode 100644
index 0000000..0fe3416
--- /dev/null
+++ b/chrome/browser/chromeos/login/merge_session_throttle.cc
@@ -0,0 +1,103 @@
+// Copyright (c) 2013 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/login/merge_session_throttle.h"
+
+#include "base/bind.h"
+#include "base/logging.h"
+#include "base/memory/singleton.h"
+#include "base/metrics/histogram.h"
+#include "base/string_util.h"
+#include "chrome/browser/chromeos/login/login_utils.h"
+#include "chrome/browser/google/google_util.h"
+#include "chrome/browser/net/chrome_url_request_context.h"
+#include "chrome/common/url_constants.h"
+#include "content/public/browser/browser_thread.h"
+#include "content/public/browser/render_view_host.h"
+#include "content/public/browser/resource_controller.h"
+#include "content/public/browser/web_contents.h"
+#include "net/base/net_errors.h"
+#include "net/base/net_util.h"
+#include "net/base/network_change_notifier.h"
+#include "net/url_request/url_request.h"
+#include "net/url_request/url_request_context.h"
+
+using content::BrowserThread;
+using content::RenderViewHost;
+using content::WebContents;
+
+namespace {
+
+void ShowDeleayedLoadingPage(
+    int render_process_id,
+    int render_view_id,
+    const GURL& url,
+    const chromeos::MergeSessionLoadPage::CompletionCallback& callback) {
+  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
+
+  // Check again on UI thread and proceed if it's connected.
+  if (chromeos::UserManager::Get()->GetMergeSessionState() !=
+          chromeos::UserManager::MERGE_STATUS_IN_PROCESS) {
+    BrowserThread::PostTask(
+        BrowserThread::IO, FROM_HERE, callback);
+  } else {
+    RenderViewHost* render_view_host =
+        RenderViewHost::FromID(render_process_id, render_view_id);
+    WebContents* web_contents = render_view_host ?
+        WebContents::FromRenderViewHost(render_view_host) : NULL;
+    // There is a chance that the tab closed after we decided to show
+    // the offline page on the IO thread and before we actually show the
+    // offline page here on the UI thread.
+    if (web_contents)
+      (new chromeos::MergeSessionLoadPage(web_contents, url, callback))->Show();
+  }
+}
+
+}  // namespace
+
+MergeSessionThrottle::MergeSessionThrottle(int render_process_id,
+                                           int render_view_id,
+                                           net::URLRequest* request)
+    : render_process_id_(render_process_id),
+      render_view_id_(render_view_id),
+      request_(request) {
+}
+
+MergeSessionThrottle::~MergeSessionThrottle() {
+  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::IO));
+}
+
+void MergeSessionThrottle::WillStartRequest(bool* defer) {
+  if (!ShouldShowMergeSessionPage(request_->url()))
+    return;
+
+  DVLOG(1) << "WillStartRequest: url=" << request_->url();
+  BrowserThread::PostTask(
+      BrowserThread::UI,
+      FROM_HERE,
+      base::Bind(
+          &ShowDeleayedLoadingPage,
+          render_process_id_,
+          render_view_id_,
+          request_->url(),
+          base::Bind(
+              &MergeSessionThrottle::OnBlockingPageComplete,
+              AsWeakPtr())));
+  *defer = true;
+}
+
+void MergeSessionThrottle::OnBlockingPageComplete() {
+  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::IO));
+  controller()->Resume();
+}
+
+bool MergeSessionThrottle::ShouldShowMergeSessionPage(const GURL& url) const {
+  // If we are loading google properties while merge session is in progress,
+  // we will show delayed loading page instead.
+  return !net::NetworkChangeNotifier::IsOffline() &&
+         google_util::IsGoogleHostname(url.host(),
+                                       google_util::ALLOW_SUBDOMAIN) &&
+         chromeos::UserManager::Get()->GetMergeSessionState() ==
+             chromeos::UserManager::MERGE_STATUS_IN_PROCESS;
+}
diff --git a/chrome/browser/chromeos/login/merge_session_throttle.h b/chrome/browser/chromeos/login/merge_session_throttle.h
new file mode 100644
index 0000000..ad1b258
--- /dev/null
+++ b/chrome/browser/chromeos/login/merge_session_throttle.h
@@ -0,0 +1,51 @@
+// Copyright (c) 2013 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 CHROME_BROWSER_CHROMEOS_LOGIN_MERGE_SESSION_THROTTLE_H_
+#define CHROME_BROWSER_CHROMEOS_LOGIN_MERGE_SESSION_THROTTLE_H_
+
+#include "base/memory/ref_counted.h"
+#include "base/memory/weak_ptr.h"
+#include "chrome/browser/chromeos/login/merge_session_load_page.h"
+#include "content/public/browser/resource_throttle.h"
+#include "net/base/completion_callback.h"
+
+namespace net {
+class URLRequest;
+}
+
+// Used to show an interstitial page while merge session process (cookie
+// reconstruction from OAuth2 refresh token in ChromeOS login) is still in
+// progress while we are attempting to load a google property.
+class MergeSessionThrottle
+    : public content::ResourceThrottle,
+      public base::SupportsWeakPtr<MergeSessionThrottle> {
+ public:
+  MergeSessionThrottle(int render_process_id,
+                       int render_view_id,
+                       net::URLRequest* request);
+  virtual ~MergeSessionThrottle();
+
+  // content::ResourceThrottle implementation:
+  virtual void WillStartRequest(bool* defer) OVERRIDE;
+
+ private:
+  // MergeSessionLoadPage callback.
+  void OnBlockingPageComplete();
+
+  // Erase the state associated with a deferred load request.
+  void ClearRequestInfo();
+  bool IsRemote(const GURL& url) const;
+
+  // True if we should show the merge session in progress page.
+  bool ShouldShowMergeSessionPage(const GURL& url) const;
+
+  int render_process_id_;
+  int render_view_id_;
+  net::URLRequest* request_;
+
+  DISALLOW_COPY_AND_ASSIGN(MergeSessionThrottle);
+};
+
+#endif  // CHROME_BROWSER_CHROMEOS_LOGIN_MERGE_SESSION_THROTTLE_H_
diff --git a/chrome/browser/chromeos/login/mock_user_manager.h b/chrome/browser/chromeos/login/mock_user_manager.h
index a7e7153..ab4a35b 100644
--- a/chrome/browser/chromeos/login/mock_user_manager.h
+++ b/chrome/browser/chromeos/login/mock_user_manager.h
@@ -66,6 +66,8 @@ class MockUserManager : public UserManager {
   MOCK_METHOD1(RemoveObserver, void(UserManager::Observer*));
   MOCK_METHOD0(NotifyLocalStateChanged, void(void));
   MOCK_METHOD0(CreateLocallyManagedUserRecord, void(void));
+  MOCK_CONST_METHOD0(GetMergeSessionState, MergeSessionState(void));
+  MOCK_METHOD1(SetMergeSessionState, void(MergeSessionState));
 
   // You can't mock this function easily because nobody can create User objects
   // but the UserManagerImpl and us.
diff --git a/chrome/browser/chromeos/login/oauth2_login_manager.cc b/chrome/browser/chromeos/login/oauth2_login_manager.cc
index 2497fb5..c719a28b 100644
--- a/chrome/browser/chromeos/login/oauth2_login_manager.cc
+++ b/chrome/browser/chromeos/login/oauth2_login_manager.cc
@@ -242,6 +242,7 @@ void OAuth2LoginManager::OnSessionMergeSuccess() {
   UMA_HISTOGRAM_ENUMERATION("OAuth2Login.SessionRestore",
                             SESSION_RESTORE_SUCCESS,
                             SESSION_RESTORE_COUNT);
+  delegate_->OnCompletedMergeSession();
 }
 
 void OAuth2LoginManager::OnSessionMergeFailure() {
@@ -253,6 +254,7 @@ void OAuth2LoginManager::OnSessionMergeFailure() {
   UMA_HISTOGRAM_ENUMERATION("OAuth2Login.SessionRestore",
                             SESSION_RESTORE_MERGE_SESSION_FAILED,
                             SESSION_RESTORE_COUNT);
+  delegate_->OnCompletedMergeSession();
 }
 
 void OAuth2LoginManager::StartTokenService(
diff --git a/chrome/browser/chromeos/login/oauth_login_manager.h b/chrome/browser/chromeos/login/oauth_login_manager.h
index bb55f5d..211d615 100644
--- a/chrome/browser/chromeos/login/oauth_login_manager.h
+++ b/chrome/browser/chromeos/login/oauth_login_manager.h
@@ -5,8 +5,6 @@
 #ifndef CHROME_BROWSER_CHROMEOS_LOGIN_OAUTH_LOGIN_MANAGER_H_
 #define CHROME_BROWSER_CHROMEOS_LOGIN_OAUTH_LOGIN_MANAGER_H_
 
-#include <string>
-
 #include "base/memory/ref_counted.h"
 #include "net/url_request/url_request_context_getter.h"
 
@@ -32,6 +30,9 @@ class OAuthLoginManager {
    public:
     virtual ~Delegate() {}
 
+    // Raised when merge session is completed.
+    virtual void OnCompletedMergeSession() = 0;
+
     // Raised when cookie jar authentication is successfully completed.
     virtual void OnCompletedAuthentication(Profile* user_profile) = 0;
 
diff --git a/chrome/browser/chromeos/login/user_manager.h b/chrome/browser/chromeos/login/user_manager.h
index 13a95dd..168ea81 100644
--- a/chrome/browser/chromeos/login/user_manager.h
+++ b/chrome/browser/chromeos/login/user_manager.h
@@ -21,13 +21,27 @@ class UserImageManager;
 // who have logged into this Chrome OS device before and updating that list.
 class UserManager {
  public:
+  // Status of merge sessions process which is responsible for exchanging
+  // user OAuth2 refresh token for GAIA cookies.
+  enum MergeSessionState {
+    // Session merge hasn't started yet.
+    MERGE_STATUS_NOT_STARTED,
+    // Session merge is in process.
+    MERGE_STATUS_IN_PROCESS,
+    // Session merge is completed.
+    MERGE_STATUS_DONE,
+  };
+
   // Interface that observers of UserManager must implement in order
   // to receive notification when local state preferences is changed
   class Observer {
    public:
-    // Called when the local state preferences is changed
+    // Called when the local state preferences is changed.
     virtual void LocalStateChanged(UserManager* user_manager) = 0;
 
+    // Called when merge session state is changed.
+    virtual void MergeSessionStateChanged(MergeSessionState state) {}
+
    protected:
     virtual ~Observer() {}
   };
@@ -211,6 +225,12 @@ class UserManager {
   // or restart after crash.
   virtual bool IsSessionStarted() const = 0;
 
+  // Returns merge session status.
+  virtual MergeSessionState GetMergeSessionState() const = 0;
+
+  // Changes merge session status.
+  virtual void SetMergeSessionState(MergeSessionState status) = 0;
+
   // Returns true when the browser has crashed and restarted during the current
   // user's session.
   virtual bool HasBrowserRestarted() const = 0;
diff --git a/chrome/browser/chromeos/login/user_manager_impl.cc b/chrome/browser/chromeos/login/user_manager_impl.cc
index 8c4450c..d56aa50 100644
--- a/chrome/browser/chromeos/login/user_manager_impl.cc
+++ b/chrome/browser/chromeos/login/user_manager_impl.cc
@@ -181,6 +181,7 @@ UserManagerImpl::UserManagerImpl()
       is_current_user_new_(false),
       is_current_user_ephemeral_regular_user_(false),
       ephemeral_users_enabled_(false),
+      merge_session_state_(MERGE_STATUS_NOT_STARTED),
       observed_sync_service_(NULL),
       user_image_manager_(new UserImageManagerImpl) {
   // UserManager instance should be used only on UI thread.
@@ -725,6 +726,19 @@ bool UserManagerImpl::IsSessionStarted() const {
   return session_started_;
 }
 
+UserManager::MergeSessionState UserManagerImpl::GetMergeSessionState() const {
+  return merge_session_state_;
+}
+
+void UserManagerImpl::SetMergeSessionState(
+    UserManager::MergeSessionState state) {
+  if (merge_session_state_ == state)
+    return;
+
+  merge_session_state_ = state;
+  NotifyMergeSessionStateChanged();
+}
+
 bool UserManagerImpl::HasBrowserRestarted() const {
   CommandLine* command_line = CommandLine::ForCurrentProcess();
   return base::chromeos::IsRunningOnChromeOS() &&
@@ -1087,4 +1101,10 @@ void UserManagerImpl::NotifyUserListChanged() {
       content::NotificationService::NoDetails());
 }
 
+void UserManagerImpl::NotifyMergeSessionStateChanged() {
+  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
+  FOR_EACH_OBSERVER(UserManager::Observer, observer_list_,
+                    MergeSessionStateChanged(merge_session_state_));
+}
+
 }  // namespace chromeos
diff --git a/chrome/browser/chromeos/login/user_manager_impl.h b/chrome/browser/chromeos/login/user_manager_impl.h
index 9e0af15..1594d18 100644
--- a/chrome/browser/chromeos/login/user_manager_impl.h
+++ b/chrome/browser/chromeos/login/user_manager_impl.h
@@ -90,6 +90,8 @@ class UserManagerImpl
   virtual bool IsLoggedInAsLocallyManagedUser() const OVERRIDE;
   virtual bool IsLoggedInAsStub() const OVERRIDE;
   virtual bool IsSessionStarted() const OVERRIDE;
+  virtual MergeSessionState GetMergeSessionState() const OVERRIDE;
+  virtual void SetMergeSessionState(MergeSessionState status) OVERRIDE;
   virtual bool HasBrowserRestarted() const OVERRIDE;
   virtual bool IsUserNonCryptohomeDataEphemeral(
       const std::string& email) const OVERRIDE;
@@ -171,6 +173,9 @@ class UserManagerImpl
   // Notifies the UI about a change to the user list.
   void NotifyUserListChanged();
 
+  // Notifies observers that merge session state had changed.
+  void NotifyMergeSessionStateChanged();
+
   // Interface to the signed settings store.
   CrosSettings* cros_settings_;
 
@@ -214,8 +219,8 @@ class UserManagerImpl
   // policy yet.
   bool ephemeral_users_enabled_;
 
-  // True if user pod row is showed at login screen.
-  bool show_users_;
+  // Merge session state (cookie restore process state).
+  MergeSessionState merge_session_state_;
 
   // Cached name of device owner. Defaults to empty string if the value has not
   // been read from trusted device policy yet.
diff --git a/chrome/browser/renderer_host/chrome_resource_dispatcher_host_delegate.cc b/chrome/browser/renderer_host/chrome_resource_dispatcher_host_delegate.cc
index bf74c49..d35292b 100644
--- a/chrome/browser/renderer_host/chrome_resource_dispatcher_host_delegate.cc
+++ b/chrome/browser/renderer_host/chrome_resource_dispatcher_host_delegate.cc
@@ -60,6 +60,7 @@
 
 #if defined(OS_CHROMEOS)
 #include "chrome/browser/chromeos/extensions/file_browser_resource_throttle.h"
+#include "chrome/browser/chromeos/login/merge_session_throttle.h"
 // TODO(oshima): Enable this for other platforms.
 #include "chrome/browser/renderer_host/offline_resource_throttle.h"
 #endif
@@ -162,6 +163,11 @@ void ChromeResourceDispatcherHostDelegate::RequestBeginning(
     // block unsafe site after we remove offline page.
     throttles->push_back(new OfflineResourceThrottle(
         child_id, route_id, request, appcache_service));
+    // Add interstitial page while merge session process (cookie
+    // reconstruction from OAuth2 refresh token in ChromeOS login) is still in
+    // progress while we are attempting to load a google property.
+    throttles->push_back(new MergeSessionThrottle(
+        child_id, route_id, request));
   }
 #endif
 
diff --git a/chrome/browser/resources/chromeos/merge_session_load.html b/chrome/browser/resources/chromeos/merge_session_load.html
new file mode 100644
index 0000000..54bb0ec5
--- /dev/null
+++ b/chrome/browser/resources/chromeos/merge_session_load.html
@@ -0,0 +1,61 @@
+<!DOCTYPE html>
+<html i18n-values="dir:textdirection">
+<head>
+<title i18n-content="title">
+</title>
+<style>
+html {
+  height: 100%;
+}
+body {
+  -webkit-user-select: none;
+  background: white;
+  color: #000;
+  display: -webkit-box;
+  font-family: arial, sans-serif;
+  height: 100%;
+  margin: 0;
+  padding: 0;
+  visibility: hidden;
+  width: 100%;
+}
+
+.header {
+  font-family: Sans-serif;
+  padding: 3px;
+  width: 80%;
+}
+</style>
+<script src="../../../../ui/webui/resources/js/local_strings.js"></script>
+
+<script>
+var localStrings = new LocalStrings();
+
+function sendCommand(cmd) {
+  window.domAutomationController.setAutomationId(1);
+  window.domAutomationController.send(cmd);
+}
+
+// Show the interstitial page.
+function showPage() {
+  document.body.style.visibility = 'visible';
+}
+
+// Show the interstitial page.
+function forceLoad() {
+  sendCommand('proceed');
+}
+
+document.addEventListener('DOMContentLoaded', function() {
+  var show_delay_time = localStrings.getString('show_delay_time');
+  var total_wait_time = localStrings.getString('total_wait_time');
+  window.setTimeout(showPage, show_delay_time);
+  window.setTimeout(forceLoad, total_wait_time);
+});
+</script>
+
+<body oncontextmenu="return false;">
+  <div class="header" i18n-content="heading">
+  </div>
+</body>
+</html>
diff --git a/chrome/chrome_browser_chromeos.gypi b/chrome/chrome_browser_chromeos.gypi
index 5af5f91..e62642f 100644
--- a/chrome/chrome_browser_chromeos.gypi
+++ b/chrome/chrome_browser_chromeos.gypi
@@ -410,6 +410,10 @@
         'browser/chromeos/login/login_wizard.h',
         'browser/chromeos/login/message_bubble.cc',
         'browser/chromeos/login/message_bubble.h',
+        'browser/chromeos/login/merge_session_load_page.cc',
+        'browser/chromeos/login/merge_session_load_page.h',
+        'browser/chromeos/login/merge_session_throttle.cc',
+        'browser/chromeos/login/merge_session_throttle.h',
         'browser/chromeos/login/network_screen.cc',
         'browser/chromeos/login/network_screen.h',
         'browser/chromeos/login/network_screen_actor.h',
diff --git a/chrome/chrome_tests_unit.gypi b/chrome/chrome_tests_unit.gypi
index 47f0ba7..4fa85a4 100644
--- a/chrome/chrome_tests_unit.gypi
+++ b/chrome/chrome_tests_unit.gypi
@@ -624,8 +624,9 @@
         'browser/chromeos/kiosk_mode/kiosk_mode_idle_logout_unittest.cc',
         'browser/chromeos/kiosk_mode/kiosk_mode_settings_unittest.cc',
         'browser/chromeos/language_preferences_unittest.cc',
-        'browser/chromeos/login/mock_auth_attempt_state_resolver.cc',
         'browser/chromeos/login/hwid_checker_unittest.cc',
+        'browser/chromeos/login/merge_session_load_page_unittest.cc',
+        'browser/chromeos/login/mock_auth_attempt_state_resolver.cc',
         'browser/chromeos/login/mock_auth_attempt_state_resolver.h',
         'browser/chromeos/login/online_attempt_unittest.cc',
         'browser/chromeos/login/parallel_authenticator_unittest.cc',