Allow cert-popup for WebView guests.

components/constrained_window/constrained_window_views.cc

Index: components/constrained_window/constrained_window_views.cc
diff --git a/components/constrained_window/constrained_window_views.cc b/components/constrained_window/constrained_window_views.cc
index 2f3c3dac2dce9dc4ea3b06eba533812f35bcb393..77e1b4b16ee4f3e82b2b6f769d627af1d6f85143 100644
--- a/components/constrained_window/constrained_window_views.cc
+++ b/components/constrained_window/constrained_window_views.cc
@@ -129,6 +129,14 @@ void UpdateWidgetModalDialogPosition(views::Widget* widget,
                             widget->GetRootView()->GetPreferredSize());
 }
 
+web_modal::PopupManager* PopupManager(content::WebContents* web_contents) {
+  // For embedded WebContents, use the embedder's WebContents for constrained
+  // window.
+  content::WebContents* top_level_web_contents =
+      guest_view::GuestViewBase::GetTopLevelWebContents(web_contents);
+  return web_modal::PopupManager::FromWebContents(top_level_web_contents);
+}
+
 views::Widget* ShowWebModalDialogViews(
     views::WidgetDelegate* dialog,
     content::WebContents* initiator_web_contents) {