[OnionSoup] Move background_sync.mojom from //content to //third_party/WebKit

content/public/common/background_sync.mojom

Index: content/public/common/background_sync.mojom
diff --git a/content/public/common/background_sync.mojom b/content/public/common/background_sync.mojom
deleted file mode 100644
index fedaf9b3274b799ab3fcf0e43b58c3609e89fe9e..0000000000000000000000000000000000000000
--- a/content/public/common/background_sync.mojom
+++ /dev/null
@@ -1,18 +0,0 @@
-// 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.
-
-module content.mojom;
-
-enum BackgroundSyncNetworkState {
-  ANY,
-  AVOID_CELLULAR,
-  ONLINE,
-  MAX=ONLINE
-};
-
-struct SyncRegistration {
-  int64 id = -1;
-  string tag = "";
-  BackgroundSyncNetworkState network_state = ONLINE;
-};