Initialize the message center as part of the testing browser process

chrome/browser/chromeos/ui/low_disk_notification_unittest.cc

Index: chrome/browser/chromeos/ui/low_disk_notification_unittest.cc
diff --git a/chrome/browser/chromeos/ui/low_disk_notification_unittest.cc b/chrome/browser/chromeos/ui/low_disk_notification_unittest.cc
index abe580ce748cbd757ffb31215dcf59fff1d7ecf6..e9dc0d061c83e2b84248a730e6e364677a89a7f1 100644
--- a/chrome/browser/chromeos/ui/low_disk_notification_unittest.cc
+++ b/chrome/browser/chromeos/ui/low_disk_notification_unittest.cc
@@ -36,7 +36,6 @@ class LowDiskNotificationTest : public testing::Test,
   void SetUp() override {
     DBusThreadManager::GetSetterForTesting()->SetCryptohomeClient(
         std::unique_ptr<CryptohomeClient>(new FakeCryptohomeClient));
-    message_center::MessageCenter::Initialize();
     low_disk_notification_.reset(new LowDiskNotification());
     low_disk_notification_->SetMessageCenterForTest(this);
     low_disk_notification_->SetNotificationIntervalForTest(
@@ -47,7 +46,6 @@ class LowDiskNotificationTest : public testing::Test,
   void TearDown() override {
     low_disk_notification_.reset();
     last_notification_.reset();
-    message_center::MessageCenter::Shutdown();
     DBusThreadManager::Shutdown();
   }