Re-Revert "[WebModals] New API for browser-scoped popup management."

apps/app_window.cc

Index: apps/app_window.cc
diff --git a/apps/app_window.cc b/apps/app_window.cc
index eb4f81a2fd7e42a57786a1902ebb162f9f370d46..8433557931e7e8189e9b8bc94197efba91a4afa0 100644
--- a/apps/app_window.cc
+++ b/apps/app_window.cc
@@ -293,10 +293,6 @@ void AppWindow::Init(const GURL& url,
   helper_.reset(new AppWebContentsHelper(
       browser_context_, extension_id_, web_contents, app_delegate_.get()));
 
-  popup_manager_.reset(
-      new web_modal::PopupManager(GetWebContentsModalDialogHost()));
-  popup_manager_->RegisterWith(web_contents);
-
   // Prevent the browser process from shutting down while this window exists.
   apps_client->IncrementKeepAliveCount();
   UpdateExtensionAppIcon();