Revert "WebUI NTP: redirect sign-in to chrome://newtab (reland)"

This reverts commit 8ba04bb7.

Reason for revert: DiceBrowserTest.EnableSyncAfterToken is failing.

Original change's description:
> WebUI NTP: redirect sign-in to chrome://newtab (reland)
> 
> 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}
> 
> TBR=thestig@chromium.org
> 
> Bug: 1015293, 1085540
> Change-Id: I05450e311b9458b6927763cbf6b4c75c0621b56e
> Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2212818
> Reviewed-by: Tibor Goldschwendt <tiborg@chromium.org>
> Reviewed-by: Lei Zhang <thestig@chromium.org>
> Commit-Queue: Tibor Goldschwendt <tiborg@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#771246}

TBR=droger@chromium.org,thestig@chromium.org,tiborg@chromium.org,aee@chromium.org

# Not skipping CQ checks because original CL landed > 1 day ago.

Bug: 1015293, 1085540
Change-Id: Ic2d3ed8d4c34373fa200563b922a4b4af0b08abe
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2213643Reviewed-by: Yutaka Hirano <yhirano@chromium.org>
Commit-Queue: Yutaka Hirano <yhirano@chromium.org>
Cr-Commit-Position: refs/heads/master@{#771459}

chrome/browser/signin/dice_browsertest.cc

@@ -28,7 +28,6 @@
 #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"
@@ -874,9 +873,7 @@ IN_PROC_BROWSER_TEST_F(DiceBrowserTest, EnableSyncAfterToken) {
             dice_request_header_);
 
   ui_test_utils::UrlLoadObserver ntp_url_observer(
-      base::FeatureList::IsEnabled(ntp_features::kWebUI)
-          ? GURL(chrome::kChromeUINewTabPageURL)
-          : GURL(chrome::kChromeSearchLocalNtpUrl),
+      GURL(chrome::kChromeSearchLocalNtpUrl),
       content::NotificationService::AllSources());
 
   WaitForSigninSucceeded();
@@ -937,7 +934,7 @@ IN_PROC_BROWSER_TEST_F(DiceBrowserTest, MAYBE_EnableSyncBeforeToken) {
             dice_request_header_);
 
   ui_test_utils::UrlLoadObserver ntp_url_observer(
-      GURL(chrome::kChromeUINewTabURL),
+      GURL(chrome::kChromeSearchLocalNtpUrl),
       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::kChromeUINewTabURL), content::Referrer(),
+      GURL(chrome::kChromeSearchLocalNtpUrl), content::Referrer(),
       ui::PAGE_TRANSITION_AUTO_TOPLEVEL, std::string());
 }
 

chrome/browser/signin/process_dice_header_delegate_impl_unittest.cc

@@ -240,8 +240,9 @@ 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::kChromeUINewTabURL) : signin_url_;
+  GURL expected_url = GetParam().show_ntp
+                          ? GURL(chrome::kChromeSearchLocalNtpUrl)
+                          : signin_url_;
   EXPECT_EQ(expected_url, web_contents()->GetVisibleURL());
   EXPECT_FALSE(show_error_called_);
   // Check that the sync signin flow is complete.
@@ -282,8 +283,9 @@ 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::kChromeUINewTabURL) : signin_url_;
+  GURL expected_url = GetParam().show_ntp
+                          ? GURL(chrome::kChromeSearchLocalNtpUrl)
+                          : signin_url_;
   EXPECT_EQ(expected_url, web_contents()->GetVisibleURL());
   // Check that the sync signin flow is complete.
   if (GetParam().signin_tab) {