Abstract WebContents/NavigationController from core TabRestore code

chrome/browser/ui/panels/panel_host.cc

Index: chrome/browser/ui/panels/panel_host.cc
diff --git a/chrome/browser/ui/panels/panel_host.cc b/chrome/browser/ui/panels/panel_host.cc
index 2fbc91c3e1dbaf20fdc04946c09bd15da83c3225..ab162a717dce834ea98fe8a37009e0d2a05698b1 100644
--- a/chrome/browser/ui/panels/panel_host.cc
+++ b/chrome/browser/ui/panels/panel_host.cc
@@ -19,6 +19,7 @@
 #include "chrome/browser/ui/panels/panel.h"
 #include "chrome/browser/ui/prefs/prefs_tab_helper.h"
 #include "components/favicon/content/content_favicon_driver.h"
+#include "components/sessions/content/content_open_tab.h"
 #include "components/ui/zoom/page_zoom.h"
 #include "components/ui/zoom/zoom_controller.h"
 #include "content/public/browser/invalidate_type.h"
@@ -66,6 +67,8 @@ void PanelHost::Init(const GURL& url) {
   SessionTabHelper::FromWebContents(web_contents_.get())->SetWindowID(
       panel_->session_id());
 
+  sessions::ContentOpenTab::CreateForWebContents(web_contents_.get());

[sky, 2015/09/16 20:04:53]

It would be nice not to have to do this in a bunch of different place. How about
ContentOpenTab::Get() that does the creation if necessary?

[blundell, 2015/09/16 20:19:42]

AFAIK lazy initialization isn't done for WebContentsUserData, although it is
what's done for KeyedService. Adding avi@ for his opinion.

[blundell, 2015/09/17 11:52:25]

Removed all the unnecessary callsites, leaving only one in tab_helpers.cc. Does
that eliminate this concern?

+
   favicon::CreateContentFaviconDriverForWebContents(web_contents_.get());
   PrefsTabHelper::CreateForWebContents(web_contents_.get());
   extensions::ChromeExtensionWebContentsObserver::CreateForWebContents(