Remove the strict dependency on WebContents for Web Notifications.

content/browser/frame_host/render_frame_host_impl.cc

Index: content/browser/frame_host/render_frame_host_impl.cc
diff --git a/content/browser/frame_host/render_frame_host_impl.cc b/content/browser/frame_host/render_frame_host_impl.cc
index e2bf47bc3e6b179002fb72ed4f1a3fdf6525290b..cc297c419aabbe3769e3c42f280048d5c0618189 100644
--- a/content/browser/frame_host/render_frame_host_impl.cc
+++ b/content/browser/frame_host/render_frame_host_impl.cc
@@ -1012,7 +1012,12 @@ void RenderFrameHostImpl::OnShowDesktopNotification(
 
   base::Closure cancel_callback;
   GetContentClient()->browser()->ShowDesktopNotification(
-      params, this, delegate.Pass(), &cancel_callback);
+      params,
+      GetSiteInstance()->GetBrowserContext(),
+      GetProcess()->GetID(),
+      delegate.Pass(),
+      &cancel_callback);
+
   cancel_notification_callbacks_[notification_id] = cancel_callback;
 }