chrome: win: Fix taskbar grouping of PiP and DevTools windows (fixes #3641)

libcef/browser/chrome/browser_delegate.h

@@ -141,6 +141,10 @@ class BrowserDelegate : public content::WebContentsDelegate {
 
   // Called at the end of a fullscreen transition.
   virtual void WindowFullscreenStateChanged() {}
+
+  // Returns true if this browser has a Views-hosted opener. Only
+  // applicable for Browsers of type picture_in_picture and devtools.
+  virtual bool HasViewsHostedOpener() const { return false; }
 };
 
 }  // namespace cef

libcef/browser/chrome/chrome_browser_delegate.cc

@@ -426,6 +426,12 @@ void ChromeBrowserDelegate::WindowFullscreenStateChanged() {
 #endif
 }
 
+bool ChromeBrowserDelegate::HasViewsHostedOpener() const {
+  DCHECK(browser_->is_type_picture_in_picture() ||
+         browser_->is_type_devtools());
+  return opener_host_ && opener_host_->is_views_hosted();
+}
+
 void ChromeBrowserDelegate::WebContentsCreated(
     content::WebContents* source_contents,
     int opener_render_process_id,

libcef/browser/chrome/chrome_browser_delegate.h

@@ -81,6 +81,7 @@ class ChromeBrowserDelegate : public cef::BrowserDelegate {
   const std::optional<SkRegion> GetDraggableRegion() const override;
   void UpdateDraggableRegion(const SkRegion& region) override;
   void WindowFullscreenStateChanged() override;
+  bool HasViewsHostedOpener() const override;
 
   // WebContentsDelegate methods:
   void WebContentsCreated(content::WebContents* source_contents,

patch/patch.cfg

@@ -728,5 +728,10 @@ patches = [
     # alloy: Don't create GPUCache directory when cache_path is empty.
     # https://github.com/chromiumembedded/cef/issues/3617
     'name': 'content_renderer_host_3617'
-  }
+  },
+  {
+    # chrome: win: Fix taskbar grouping of PiP and DevTools windows.
+    # https://github.com/chromiumembedded/cef/issues/3641
+    'name': 'win_taskbar_group_3641'
+  },
 ]

patch/patches/win_taskbar_group_3641.patch

@@ -0,0 +1,29 @@
+diff --git chrome/browser/ui/views/frame/browser_window_property_manager_win.cc chrome/browser/ui/views/frame/browser_window_property_manager_win.cc
+index 1a62480aee22c..9da572856c03b 100644
+--- chrome/browser/ui/views/frame/browser_window_property_manager_win.cc
++++ chrome/browser/ui/views/frame/browser_window_property_manager_win.cc
+@@ -8,6 +8,7 @@
+ #include "base/functional/bind.h"
+ #include "base/strings/utf_string_conversions.h"
+ #include "base/win/windows_version.h"
++#include "cef/libcef/features/features.h"
+ #include "chrome/browser/browser_process.h"
+ #include "chrome/browser/profiles/profile.h"
+ #include "chrome/browser/profiles/profile_manager.h"
+@@ -49,6 +50,16 @@ void BrowserWindowPropertyManager::UpdateWindowProperties() {
+   const Browser* browser = view_->browser();
+   Profile* profile = browser->profile();
+ 
++#if BUILDFLAG(ENABLE_CEF)
++  if (browser->cef_delegate() &&
++        (browser->is_type_picture_in_picture() ||
++         browser->is_type_devtools()) &&
++        browser->cef_delegate()->HasViewsHostedOpener()) {
++    // Don't create a separate taskbar group.
++    return;
++  }
++#endif
++
+   // Set the app user model id for this application to that of the application
+   // name. See http://crbug.com/7028.
+   std::wstring app_id =