[signin] Force light mode for the reauth confirmation dialog

Gaia Reauth page doesn't support dark mode. The reauth confirmation
dialog is shown right before the Gaia Reauth. The transition between
the two dialogs looks weird if one of them is dark and another one is
light.

The reauth confirmation dialog should also be displayed in light mode
until Gaia Reauth supports dark mode.

Bug: 1115930
Change-Id: I535b62e6a8782406bb30ac7521060468f7e7afc0
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2362928
Commit-Queue: Alex Ilin <alexilin@chromium.org>
Reviewed-by: David Roger <droger@chromium.org>
Cr-Commit-Position: refs/heads/master@{#799113}

chrome/browser/ui/signin_reauth_view_controller.cc

@@ -28,7 +28,9 @@
 #include "content/public/browser/site_instance.h"
 #include "content/public/browser/web_contents.h"
 #include "content/public/browser/web_contents_observer.h"
+#include "content/public/common/web_preferences.h"
 #include "google_apis/gaia/gaia_urls.h"
+#include "third_party/blink/public/common/css/preferred_color_scheme.h"
 
 namespace {
 
@@ -309,8 +311,15 @@ void SigninReauthViewController::ShowReauthConfirmationDialog() {
           browser_, account_id_, access_point_);
   dialog_delegate_observer_.Add(dialog_delegate_);
 
-  SigninReauthUI* web_dialog_ui = static_cast<SigninReauthUI*>(
-      dialog_delegate_->GetWebContents()->GetWebUI()->GetController());
+  // Gaia Reauth page doesn't support dark mode. Force the confirmation dialog
+  // to use the light mode as well to match the style.
+  auto* web_contents = dialog_delegate_->GetWebContents();
+  auto prefs = web_contents->GetOrCreateWebPreferences();
+  prefs.preferred_color_scheme = blink::PreferredColorScheme::kLight;
+  web_contents->SetWebPreferences(prefs);
+
+  SigninReauthUI* web_dialog_ui =
+      web_contents->GetWebUI()->GetController()->GetAs<SigninReauthUI>();
   web_dialog_ui->InitializeMessageHandlerWithReauthController(this);
 }
 

chrome/browser/ui/views/profiles/signin_view_controller_delegate_views.cc

@@ -264,12 +264,9 @@ void SigninViewControllerDelegateViews::DisplayModal() {
       NOTREACHED() << "Unsupported dialog modal type " << dialog_modal_type_;
   }
   if (should_show_close_button_) {
-    SkColor border_color = GetNativeTheme()->ShouldUseDarkColors()
-                               ? gfx::kGoogleGrey900
-                               : SK_ColorWHITE;
     GetBubbleFrameView()->SetBubbleBorder(std::make_unique<views::BubbleBorder>(
         views::BubbleBorder::NONE, views::BubbleBorder::BIG_SHADOW,
-        border_color));
+        SK_ColorWHITE));
   }
 
   content_view_->RequestFocus();

chrome/browser/ui/webui/signin/signin_reauth_ui.cc

@@ -22,6 +22,7 @@
 #include "components/signin/public/identity_manager/account_info.h"
 #include "components/signin/public/identity_manager/consent_level.h"
 #include "components/signin/public/identity_manager/identity_manager.h"
+#include "content/public/browser/web_ui_controller.h"
 #include "content/public/browser/web_ui_data_source.h"
 #include "google_apis/gaia/core_account_id.h"
 #include "services/network/public/mojom/content_security_policy.mojom.h"
@@ -159,3 +160,5 @@ void SigninReauthUI::AddStringResource(content::WebUIDataSource* source,
 
   js_localized_string_to_ids_.emplace_back(sanitized_string, ids);
 }
+
+WEB_UI_CONTROLLER_TYPE_IMPL(SigninReauthUI)

chrome/browser/ui/webui/signin/signin_reauth_ui.h

@@ -9,6 +9,7 @@
 #include <vector>
 
 #include "chrome/browser/ui/webui/signin/signin_web_dialog_ui.h"
+#include "content/public/browser/web_ui_controller.h"
 
 class Browser;
 class SigninReauthViewController;
@@ -16,7 +17,7 @@ class SigninReauthViewController;
 namespace content {
 class WebUI;
 class WebUIDataSource;
-}
+}  // namespace content
 
 // WebUI controller for the signin reauth dialog.
 //
@@ -60,6 +61,8 @@ class SigninReauthUI : public SigninWebDialogUI {
 
   // For consent auditing.
   std::vector<std::pair<std::string, int>> js_localized_string_to_ids_;
+
+  WEB_UI_CONTROLLER_TYPE_DECL();
 };
 
 #endif  // CHROME_BROWSER_UI_WEBUI_SIGNIN_SIGNIN_REAUTH_UI_H_