[cr149] IsWebContentsVisible cannot be override through Browser

Browser doesn't inherit from `ChromeWebModalDialogManagerDelegate`
anymore. This change fixes our code by directly patching
`ChromeWebModalDialogManagerDelegate` to have an override for this
method.

Chromium changes:
https://chromium.googlesource.com/chromium/src/+/083c2a8b08fff93b74aac4f4acd89c5d1fb206ea

commit 083c2a8b08fff93b74aac4f4acd89c5d1fb206ea
Author: Qikai <qikaizhong@microsoft.com>
Date:   Tue Apr 21 22:53:26 2026 -0700

    [bedrock] Move ChromeWebModalDialogManagerDelegate to BrowserWindowFeatures

    Extract ChromeWebModalDialogManagerDelegate from Browser into a new
    BrowserWindowModalDialogDelegate owned by BrowserWindowFeatures. The
    new class manages per-tab WebContentsModalDialogManager delegate
    registration via TabStripModelObserver and handles tab blocking,
    fullscreen exit, and dialog host lookup.

    Browser retains a thin SetWebContentsBlocked() override for
    DesktopBrowserWindowCapabilitiesDelegate, forwarding to the feature.
    DevTools scrim visibility uses a callback pattern subscribed by
    BrowserView.

    Bug: 496674143
    Change-Id: Ia8aea00b733e113c5ca9e9e79d28a37061eb8ced
    Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/7738543
    Reviewed-by: Thomas Lukaszewicz <tluk@chromium.org>
    Commit-Queue: Qikai Zhong <qikaizhong@microsoft.com>
    Cr-Commit-Position: refs/heads/main@{#1618668}

browser/ui/brave_browser.cc

@@ -323,20 +323,6 @@ bool BraveBrowser::NormalBrowserSupportsWindowFeature(
                                                      check_can_support);
 }
 
-bool BraveBrowser::IsWebContentsVisible(content::WebContents* web_contents) {
-  const auto original_visible = Browser::IsWebContentsVisible(web_contents);
-  auto* tab = tabs::TabInterface::MaybeGetFromContents(web_contents);
-  if (!tab) {
-    return original_visible;
-  }
-
-  if (original_visible && !tab->IsActivated()) {
-    return false;
-  }
-
-  return original_visible;
-}
-
 void BraveBrowser::UpdateTargetURL(content::WebContents* source,
                                    const GURL& url) {
   GURL target_url = url;

browser/ui/brave_browser.h

@@ -55,14 +55,6 @@ class BraveBrowser : public Browser {
       bool user_gesture,
       bool* was_blocked) override;
 
-  // This overrides ChromeWebModalDialogManagerDelegate::IsWebContentsVisible()
-  // and it's called from WebContentsModalDialogManager.
-  // That manager prevents web modal dialog when web contents is not visible.
-  // As we have visible but inactive tabs in split tab, this should return false
-  // when it's inactive tab. Otherwse, web modal from inactive split tab can be
-  // shown.
-  bool IsWebContentsVisible(content::WebContents* web_contents) override;
-
   void OnTabClosing(content::WebContents* contents) override;
   void TabStripEmpty() override;
 

chromium_src/chrome/browser/ui/web_modal/browser_window_modal_dialog_delegate.cc

@@ -0,0 +1,26 @@
+/* Copyright (c) 2025 The Brave Authors. All rights reserved.
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this file,
+ * You can obtain one at https://mozilla.org/MPL/2.0/. */
+
+#include "components/tabs/public/tab_interface.h"
+
+#include <chrome/browser/ui/web_modal/browser_window_modal_dialog_delegate.cc>
+
+// Overrides ChromeWebModalDialogManagerDelegate::IsWebContentsVisible() to
+// suppress web modal dialogs on inactive split tabs. A split tab can be
+// visible (i.e. rendered) but not activated, and without this override a modal
+// dialog from the inactive pane would incorrectly appear.
+bool BrowserWindowModalDialogDelegate::IsWebContentsVisible(
+    content::WebContents* web_contents) {
+  const bool original_visible =
+      ChromeWebModalDialogManagerDelegate::IsWebContentsVisible(web_contents);
+  auto* tab = tabs::TabInterface::MaybeGetFromContents(web_contents);
+  if (!tab) {
+    return original_visible;
+  }
+  if (original_visible && !tab->IsActivated()) {
+    return false;
+  }
+  return original_visible;
+}

patches/chrome-browser-ui-web_modal-browser_window_modal_dialog_delegate.h.patch

@@ -0,0 +1,12 @@
+diff --git a/chrome/browser/ui/web_modal/browser_window_modal_dialog_delegate.h b/chrome/browser/ui/web_modal/browser_window_modal_dialog_delegate.h
+index b72d333bb51b47a2e5e1baaaab7659bc2ff7963a..f58b1f1a660d2405eadbf2737ca5f29720490ecf 100644
+--- a/chrome/browser/ui/web_modal/browser_window_modal_dialog_delegate.h
++++ b/chrome/browser/ui/web_modal/browser_window_modal_dialog_delegate.h
+@@ -31,6 +31,7 @@ class BrowserWindowModalDialogDelegate
+       BrowserWindowInterface* browser);
+ 
+   // ChromeWebModalDialogManagerDelegate:
++  bool IsWebContentsVisible(content::WebContents* web_contents) override;
+   void SetWebContentsBlocked(content::WebContents* web_contents,
+                              bool blocked) override;
+   web_modal::WebContentsModalDialogHost* GetWebContentsModalDialogHost(

rewrite/chrome/browser/ui/web_modal/browser_window_modal_dialog_delegate.h.toml

@@ -0,0 +1,9 @@
+# Copyright (c) 2025 The Brave Authors. All rights reserved.
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this file,
+# You can obtain one at https://mozilla.org/MPL/2.0/.
+
+[[substitution]]
+description = '''IsWebContentsVisible override for inactive split tabs''''
+re_pattern = '(  // ChromeWebModalDialogManagerDelegate:\n)'
+replace = '''\1  bool IsWebContentsVisible(content::WebContents* web_contents) override;\n'''