Move web modal dialog manager files into the constrained_window component.

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 def5232fc9782603559d380c6499264f1c8ac6b5..37d580988a66721c7a47080dc5be34df2daf7d23 100644
--- a/components/constrained_window/constrained_window_views.cc
+++ b/components/constrained_window/constrained_window_views.cc
@@ -141,8 +141,7 @@ views::Widget* ShowWebModalDialogViews(
   content::WebContents* web_contents =
       guest_view::GuestViewBase::GetTopLevelWebContents(initiator_web_contents);
   views::Widget* widget = CreateWebModalDialogViews(dialog, web_contents);
-  web_modal::WebContentsModalDialogManager::FromWebContents(web_contents)
-      ->ShowModalDialog(widget->GetNativeWindow());
+  ShowModalDialog(widget->GetNativeWindow(), web_contents);
   return widget;
 }