athena: Add the concept of Activity and related managers.

athena/activity/activity_manager_impl.cc

+// Copyright 2014 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 "athena/activity/public/activity_manager.h"
+
+#include <algorithm>
+#include <vector>
+
+#include "athena/activity/public/activity_view_manager.h"
+#include "base/logging.h"
+
+namespace athena {
+
+namespace {
+
+ActivityManager* instance = NULL;
+
+class ActivityManagerImpl : public ActivityManager {
+ public:
+  ActivityManagerImpl() {
+    CHECK(!instance);
+    instance = this;
+  }
+  virtual ~ActivityManagerImpl() {
+    CHECK_EQ(this, instance);
+    instance = NULL;
+  }
+
+  // ActivityManager:
+  virtual void AddActivity(Activity* activity) OVERRIDE {
+    CHECK(activities_.end() == std::find(activities_.begin(),
+                                         activities_.end(),
+                                         activity));
+    activities_.push_back(activity);
+    ActivityViewManager* manager = ActivityViewManager::Get();
+    manager->AddActivity(activity);
+  }
+
+  virtual void RemoveActivity(Activity* activity) OVERRIDE {
+    std::vector<Activity*>::iterator find = std::find(activities_.begin(),
+                                                      activities_.end(),
+                                                      activity);
+    if (find != activities_.end()) {
+      activities_.erase(find);
+
+      ActivityViewManager* manager = ActivityViewManager::Get();
+      manager->AddActivity(activity);
+    }
+  }
+
+  virtual void UpdateActivity(Activity* activity) OVERRIDE {
+    ActivityViewManager* manager = ActivityViewManager::Get();
+    manager->UpdateActivity(activity);
+  }
+
+ private:
+  std::vector<Activity*> activities_;
+
+  DISALLOW_COPY_AND_ASSIGN(ActivityManagerImpl);
+};
+
+}  // namespace
+
+// static
+ActivityManager* ActivityManager::Create() {
+  new ActivityManagerImpl();
+  CHECK(instance);
+
+  ActivityViewManager::Create();
+
+  return instance;
+}
+
+ActivityManager* ActivityManager::Get() {
+  return instance;
+}
+
+void ActivityManager::Shutdown() {
+  ActivityViewManager::Shutdown();
+
+  CHECK(instance);
+  delete instance;
+}
+
+}  // namespace athena