Fix closing tab count for all edge cases

Author: Jai-JAP

src/browser/base/content/browser-js.patch

@@ -1,5 +1,5 @@
 diff --git a/browser/base/content/browser.js b/browser/base/content/browser.js
-index 05f6aec3dac31231e15cb316f6e06d66ee87bea9..3bbbe8553777056798ea9ddce1744a8e48848a37 100644
+index 05f6aec3dac31231e15cb316f6e06d66ee87bea9..6f0a50684dc3aae6b22fce14aa7f855e8e06136a 100644
 --- a/browser/base/content/browser.js
 +++ b/browser/base/content/browser.js
 @@ -29,6 +29,7 @@ ChromeUtils.defineESModuleGetters(this, {
@@ -19,6 +19,33 @@ index 05f6aec3dac31231e15cb316f6e06d66ee87bea9..3bbbe8553777056798ea9ddce1744a8e
      PictureInPicture.updateUrlbarToggle(gBrowser.selectedBrowser);
 
      if (!gMultiProcessBrowser) {
+@@ -4302,7 +4305,7 @@ function warnAboutClosingWindow() {
+ 
+   if (!isPBWindow && !toolbar.visible) {
+     return gBrowser.warnAboutClosingTabs(
+-      gBrowser.openTabs.length,
++      gBrowser.visibleTabs.filter(t => t.getAttribute("pending")!=="true").length,
+       gBrowser.closingTabsEnum.ALL
+     );
+   }
+@@ -4342,7 +4345,7 @@ function warnAboutClosingWindow() {
+     return (
+       isPBWindow ||
+       gBrowser.warnAboutClosingTabs(
+-        gBrowser.openTabs.length,
++        gBrowser.visibleTabs.filter(t => t.getAttribute("pending")!=="true").length,
+         gBrowser.closingTabsEnum.ALL
+       )
+     );
+@@ -4367,7 +4370,7 @@ function warnAboutClosingWindow() {
+     AppConstants.platform != "macosx" ||
+     isPBWindow ||
+     gBrowser.warnAboutClosingTabs(
+-      gBrowser.openTabs.length,
++      gBrowser.visibleTabs.filter(t => t.getAttribute("pending")!=="true").length,
+       gBrowser.closingTabsEnum.ALL
+     )
+   );
 @@ -4630,7 +4633,7 @@ function switchToTabHavingURI(
        ignoreQueryString || replaceQueryString,
        ignoreFragmentWhenComparing