arc: Show custom notification via notification surface

chrome/browser/chrome_browser_main_extra_parts_exo.cc

 // Copyright 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "chrome/browser/chrome_browser_main_extra_parts_exo.h"
 
 #include "base/memory/ptr_util.h"
 
 #if defined(USE_GLIB)
 #include <glib.h>
 #endif
 
 #include "base/command_line.h"
 #include "base/macros.h"
 #include "base/message_loop/message_loop.h"
 #include "chrome/browser/ui/ash/ash_util.h"
 #include "chrome/common/chrome_switches.h"
 #include "components/exo/display.h"
 #include "components/exo/wayland/server.h"
 #include "content/public/browser/browser_thread.h"
+#include "ui/arc/notification/arc_custom_notification_item.h"
 
 #if defined(USE_GLIB)
 namespace {
 
 struct GLibWaylandSource : public GSource {
   // Note: The GLibWaylandSource is created and destroyed by GLib. So its
   // constructor/destructor may or may not get called.
   exo::wayland::Server* server;
   GPollFD* poll_fd;
 };
@@ skipping 85 matching lines @@
 
 void ChromeBrowserMainExtraPartsExo::PreProfileInit() {
   if (!chrome::ShouldOpenAshOnStartup())
     return;
 
   if (base::CommandLine::ForCurrentProcess()->HasSwitch(
           switches::kEnableWaylandServer)) {
     wayland_server_ = exo::wayland::Server::Create(display_.get());
     wayland_watcher_ =
         base::WrapUnique(new WaylandWatcher(wayland_server_.get()));
+
+    arc::ArcCustomNotificationItem::SetNotificationSurfaceRegistry(
+        display_->notification_surface_registry());

[Nico, 2016/06/21 18:00:29]

Does this do any interesting work? This runs very early here, so this could slow
down startup.

[xiyuan, 2016/06/21 18:03:57]

Nope. It just passes down the registry pointer to the custom notification code
and stores it there for later use.

   }
 }
 
 void ChromeBrowserMainExtraPartsExo::PostMainMessageLoopRun() {
+  arc::ArcCustomNotificationItem::SetNotificationSurfaceRegistry(nullptr);
+
   wayland_watcher_.reset();
   wayland_server_.reset();
 }