arc: Show custom notification via notification surface

ui/arc/notification/arc_notification_surface_manager.cc

Index: ui/arc/notification/arc_notification_surface_manager.cc
diff --git a/ui/arc/notification/arc_notification_surface_manager.cc b/ui/arc/notification/arc_notification_surface_manager.cc
new file mode 100644
index 0000000000000000000000000000000000000000..d816da8a234891c50acc7f88446cccabfb03685f
--- /dev/null
+++ b/ui/arc/notification/arc_notification_surface_manager.cc
@@ -0,0 +1,72 @@
+// Copyright 2016 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 "ui/arc/notification/arc_notification_surface_manager.h"
+
+#include <algorithm>
+
+#include "components/exo/notification_surface.h"
+
+namespace arc {
+
+namespace {
+
+ArcNotificationSurfaceManager* instance = nullptr;
+
+}  // namespace
+
+ArcNotificationSurfaceManager::ArcNotificationSurfaceManager() {
+  DCHECK(!instance);
+  instance = this;
+}
+
+ArcNotificationSurfaceManager::~ArcNotificationSurfaceManager() {
+  DCHECK_EQ(this, instance);
+  instance = nullptr;
+}
+
+// static
+ArcNotificationSurfaceManager* ArcNotificationSurfaceManager::Get() {
+  return instance;
+}
+
+exo::NotificationSurface* ArcNotificationSurfaceManager::GetSurface(
+    const std::string& notification_key) const {
+  auto it = notification_surface_map_.find(notification_key);
+  return it == notification_surface_map_.end() ? nullptr : it->second;
+}
+
+void ArcNotificationSurfaceManager::AddSurface(
+    exo::NotificationSurface* surface) {
+  if (notification_surface_map_.find(surface->notification_id()) !=
+      notification_surface_map_.end()) {
+    NOTREACHED();
+    return;
+  }
+
+  notification_surface_map_[surface->notification_id()] = surface;
+
+  FOR_EACH_OBSERVER(Observer, observers_, OnNotificationSurfaceAdded(surface));
+}
+
+void ArcNotificationSurfaceManager::RemoveSurface(
+    exo::NotificationSurface* surface) {
+  auto it = notification_surface_map_.find(surface->notification_id());
+  if (it == notification_surface_map_.end())
+    return;
+
+  notification_surface_map_.erase(it);
+  FOR_EACH_OBSERVER(Observer, observers_,
+                    OnNotificationSurfaceRemoved(surface));
+}
+
+void ArcNotificationSurfaceManager::AddObserver(Observer* observer) {
+  observers_.AddObserver(observer);
+}
+
+void ArcNotificationSurfaceManager::RemoveObserver(Observer* observer) {
+  observers_.RemoveObserver(observer);
+}
+
+}  // namespace arc