Try harder to work around a clang/win bug.

content/browser/background_sync/background_sync_registration_options.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 "content/browser/background_sync/background_sync_registration_options.h"
 
 namespace content {
 
 // TODO(thakis): Remove this once http://crbug.com/488634 is fixed.
-BackgroundSyncRegistrationOptions::BackgroundSyncRegistrationOptions() =
-    default;
+BackgroundSyncRegistrationOptions::BackgroundSyncRegistrationOptions()
+    : min_period(0),
+      network_state(NETWORK_STATE_ONLINE),
+      power_state(POWER_STATE_AVOID_DRAINING),
+      periodicity(SYNC_ONE_SHOT) {}
 
 bool BackgroundSyncRegistrationOptions::Equals(
     const BackgroundSyncRegistrationOptions& other) const {
   return tag == other.tag && min_period == other.min_period &&
          network_state == other.network_state &&
          power_state == other.power_state && periodicity == other.periodicity;
 }
 
 }  // namespace content