[Device Discovery] Make DialRegistry a Singleton

chrome/browser/media/router/discovery/dial/dial_registry_factory.cc

+// Copyright 2017 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/media/router/discovery/dial/dial_registry_factory.h"
+
+#include "base/time/time.h"
+#include "build/build_config.h"
+#include "chrome/browser/media/router/discovery/dial/dial_registry.h"
+#include "chrome/browser/profiles/incognito_helpers.h"
+#include "chrome/browser/profiles/profile.h"
+#include "components/keyed_service/content/browser_context_dependency_manager.h"
+
+using content::BrowserContext;
+
+namespace media_router {
+
+namespace {
+
+// How often to poll for devices.
+const int kDialRefreshIntervalSecs = 120;
+
+// We prune a device if it does not respond after this time.
+const int kDialExpirationSecs = 240;
+
+// The maximum number of devices retained at once in the registry.
+const size_t kDialMaxDevices = 256;
+
+}  // namespace
+
+// static
+scoped_refptr<DialRegistry> DialRegistryFactory::GetForBrowserContext(
+    BrowserContext* context) {
+  DCHECK(context);
+  return static_cast<DialRegistry*>(
+      GetInstance()->GetServiceForBrowserContext(context, true).get());
+}
+
+// static
+DialRegistryFactory* DialRegistryFactory::GetInstance() {
+  return base::Singleton<DialRegistryFactory>::get();
+}
+
+DialRegistryFactory::DialRegistryFactory()
+    : RefcountedBrowserContextKeyedServiceFactory(
+          "DialRegistry",
+          BrowserContextDependencyManager::GetInstance()) {}
+
+DialRegistryFactory::~DialRegistryFactory() {}
+
+content::BrowserContext* DialRegistryFactory::GetBrowserContextToUse(
+    content::BrowserContext* context) const {
+  return chrome::GetBrowserContextRedirectedInIncognito(context);
+}
+
+scoped_refptr<RefcountedKeyedService>
+DialRegistryFactory::BuildServiceInstanceFor(BrowserContext* context) const {
+  return scoped_refptr<DialRegistry>(new DialRegistry(
+      base::TimeDelta::FromSeconds(kDialRefreshIntervalSecs),
+      base::TimeDelta::FromSeconds(kDialExpirationSecs), kDialMaxDevices));
+}
+
+}  // namespace media_router