Add Now setting and migration logic.

chrome/browser/ui/app_list/google_now_extension.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/ui/app_list/google_now_extension.h"
 
+#include "base/prefs/pref_service.h"
+#include "chrome/browser/notifications/desktop_notification_service.h"
+#include "chrome/browser/notifications/desktop_notification_service_factory.h"
+#include "chrome/browser/profiles/profile.h"
+#include "chrome/common/pref_names.h"
 #include "components/variations/variations_associated_data.h"
 
 namespace {
 const char kGoogleNowExtensionFieldTrialName[] = "GoogleNowExtension";
+
+// Extension ID for previous Now notifications component.
+const char kNowNotifierId[] = "pafkbggdmjlpgkdkcbjmhmfcdpncadgh";
 };  // namespace
 
 bool GetGoogleNowExtensionId(std::string* extension_id) {
   *extension_id = variations::GetVariationParamValue(
       kGoogleNowExtensionFieldTrialName, "id");
   return !extension_id->empty();
 }
+
+// TODO(skare): Remove this if/when the Now Notifications component is
+// deprecated. http://crbug.com/459846
+void MigrateGoogleNowPrefs(Profile* profile) {
+  std::string now_extension_id;
+  if (!GetGoogleNowExtensionId(&now_extension_id))
+    return;
+
+  PrefService* prefs = profile->GetPrefs();
+  const PrefService::Preference* enabled_pref =
+      prefs->FindPreference(prefs::kGoogleNowLauncherEnabled);
+
+  // If the pref is not its default value, migration was performed.
+  if (!enabled_pref->IsDefaultValue())
+    return;
+
+  DesktopNotificationService* const notification_service =
+      DesktopNotificationServiceFactory::GetForProfile(profile);
+  bool notifier_enabled = notification_service->IsNotifierEnabled(
+      message_center::NotifierId(
+          message_center::NotifierId::APPLICATION, kNowNotifierId));
+  prefs->SetBoolean(prefs::kGoogleNowLauncherEnabled, notifier_enabled);
+}