WebUI NTP: redirect sign-in to chrome://newtab (reland #2)

This is a reland of 142274a8 with a fix
for DiceBrowserTest.EnableSyncAfterToken. Original change's info:
> Bug: 1015293
> Change-Id: Ic76e7911403a925fa46a5b5fc58eca95fa292269
> Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2209392
> Commit-Queue: Tibor Goldschwendt <tiborg@chromium.org>
> Reviewed-by: Lei Zhang <thestig@chromium.org>
> Reviewed-by: Tibor Goldschwendt <tiborg@chromium.org>
> Auto-Submit: Esmael Elmoslimany <aee@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#771116}

Bug: 1015293, 1085540
Change-Id: Ifad9f0583ef0f5ec82b20068bd186b923d4e4eaa
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2216325Reviewed-by: David Roger <droger@chromium.org>
Commit-Queue: Tibor Goldschwendt <tiborg@chromium.org>
Auto-Submit: Tibor Goldschwendt <tiborg@chromium.org>
Cr-Commit-Position: refs/heads/master@{#772253}

chrome/browser/signin/dice_browsertest.cc

@@ -27,6 +27,7 @@
 #include "chrome/browser/policy/cloud/user_policy_signin_service_internal.h"
 #include "chrome/browser/profiles/profile.h"
 #include "chrome/browser/profiles/profile_manager.h"
+#include "chrome/browser/search/ntp_features.h"
 #include "chrome/browser/signin/account_consistency_mode_manager.h"
 #include "chrome/browser/signin/account_reconcilor_factory.h"
 #include "chrome/browser/signin/chrome_device_id_helper.h"
@@ -63,7 +64,9 @@
 #include "components/variations/variations_switches.h"
 #include "content/public/browser/browser_task_traits.h"
 #include "content/public/browser/browser_thread.h"
+#include "content/public/browser/load_notification_details.h"
 #include "content/public/browser/notification_service.h"
+#include "content/public/browser/notification_types.h"
 #include "content/public/common/content_switches.h"
 #include "content/public/test/browser_test.h"
 #include "google_apis/gaia/gaia_switches.h"
@@ -871,9 +874,24 @@ IN_PROC_BROWSER_TEST_F(DiceBrowserTest, EnableSyncAfterToken) {
                                GetDeviceId().c_str()),
             dice_request_header_);
 
-  ui_test_utils::UrlLoadObserver ntp_url_observer(
-      GURL(chrome::kChromeSearchLocalNtpUrl),
-      content::NotificationService::AllSources());
+  content::WindowedNotificationObserver ntp_url_observer(
+      content::NOTIFICATION_LOAD_STOP,
+      base::BindRepeating([](const content::NotificationSource&,
+                             const content::NotificationDetails& details) {
+        auto url =
+            content::Details<content::LoadNotificationDetails>(details)->url;
+        // Some test flags (e.g. ForceWebRequestProxyForTest) can change whether
+        // the reported NTP URL is the virtual chrome://newtab or one of the
+        // concrete chrome://new-tab-page or
+        // chrome-search://local-ntp/local-ntp.html. As far as this test is
+        // concerned either URL is fine.
+        auto concrete_ntp_url =
+            base::FeatureList::IsEnabled(ntp_features::kWebUI)
+                ? GURL(chrome::kChromeUINewTabPageURL)
+                : GURL(chrome::kChromeSearchLocalNtpUrl);
+        return url == concrete_ntp_url ||
+               url == GURL(chrome::kChromeUINewTabURL);
+      }));
 
   WaitForSigninSucceeded();
   EXPECT_EQ(GetMainAccountID(), GetIdentityManager()->GetPrimaryAccountId());
@@ -933,7 +951,7 @@ IN_PROC_BROWSER_TEST_F(DiceBrowserTest, MAYBE_EnableSyncBeforeToken) {
             dice_request_header_);
 
   ui_test_utils::UrlLoadObserver ntp_url_observer(
-      GURL(chrome::kChromeSearchLocalNtpUrl),
+      GURL(chrome::kChromeUINewTabURL),
       content::NotificationService::AllSources());
 
   WaitForSigninSucceeded();

chrome/browser/signin/process_dice_header_delegate_impl.cc

@@ -24,7 +24,7 @@ namespace {
 void RedirectToNtp(content::WebContents* contents) {
   VLOG(1) << "RedirectToNtp";
   contents->GetController().LoadURL(
-      GURL(chrome::kChromeSearchLocalNtpUrl), content::Referrer(),
+      GURL(chrome::kChromeUINewTabURL), content::Referrer(),
       ui::PAGE_TRANSITION_AUTO_TOPLEVEL, std::string());
 }
 

chrome/browser/signin/process_dice_header_delegate_impl_unittest.cc

@@ -240,9 +240,8 @@ TEST_P(ProcessDiceHeaderDelegateImplTestEnableSync, EnableSync) {
       CreateDelegateAndNavigateToSignin(GetParam().signin_tab);
   delegate->EnableSync(account_id_);
   EXPECT_EQ(GetParam().callback_called, enable_sync_called_);
-  GURL expected_url = GetParam().show_ntp
-                          ? GURL(chrome::kChromeSearchLocalNtpUrl)
-                          : signin_url_;
+  GURL expected_url =
+      GetParam().show_ntp ? GURL(chrome::kChromeUINewTabURL) : signin_url_;
   EXPECT_EQ(expected_url, web_contents()->GetVisibleURL());
   EXPECT_FALSE(show_error_called_);
   // Check that the sync signin flow is complete.
@@ -283,9 +282,8 @@ TEST_P(ProcessDiceHeaderDelegateImplTestHandleTokenExchangeFailure,
   delegate->HandleTokenExchangeFailure(email_, auth_error_);
   EXPECT_FALSE(enable_sync_called_);
   EXPECT_EQ(GetParam().callback_called, show_error_called_);
-  GURL expected_url = GetParam().show_ntp
-                          ? GURL(chrome::kChromeSearchLocalNtpUrl)
-                          : signin_url_;
+  GURL expected_url =
+      GetParam().show_ntp ? GURL(chrome::kChromeUINewTabURL) : signin_url_;
   EXPECT_EQ(expected_url, web_contents()->GetVisibleURL());
   // Check that the sync signin flow is complete.
   if (GetParam().signin_tab) {