[background-sync] Remove WebSyncError and SyncCallbacks

third_party/WebKit/public/BUILD.gn

 # Copyright 2014 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.
 
 import("//build/buildflag_header.gni")
 import("//mojo/public/tools/bindings/mojom.gni")
 import("//third_party/WebKit/public/public_features.gni")
 import("//third_party/WebKit/Source/config.gni")
 import("//third_party/WebKit/Source/core/core.gni")
 import("//tools/grit/grit_rule.gni")
@@ skipping 309 matching lines @@
     "platform/WebURLLoaderClient.h",
     "platform/WebURLLoaderMockFactory.h",
     "platform/WebURLRequest.h",
     "platform/WebURLResponse.h",
     "platform/WebVector.h",
     "platform/callback/WebClosure.h",
     "platform/linux/WebFallbackFont.h",
     "platform/linux/WebFontRenderStyle.h",
     "platform/linux/WebSandboxSupport.h",
     "platform/mac/WebSandboxSupport.h",
-    "platform/modules/background_sync/WebSyncClient.h",
-    "platform/modules/background_sync/WebSyncError.h",
     "platform/modules/bluetooth/WebBluetooth.h",
     "platform/modules/bluetooth/WebBluetoothDevice.h",
     "platform/modules/bluetooth/WebBluetoothError.h",
     "platform/modules/bluetooth/WebBluetoothRemoteGATTCharacteristic.h",
     "platform/modules/bluetooth/WebBluetoothRemoteGATTCharacteristicInit.h",
     "platform/modules/bluetooth/WebBluetoothRemoteGATTService.h",
     "platform/modules/bluetooth/WebRequestDeviceOptions.h",
     "platform/modules/device_orientation/WebDeviceMotionData.h",
     "platform/modules/device_orientation/WebDeviceMotionListener.h",
     "platform/modules/device_orientation/WebDeviceOrientationData.h",
@@ skipping 419 matching lines @@
 # relegated to a separate target to avoid duplication between the variants.
 source_set("shared_typemap_traits") {
   visibility = [ ":*" ]
   sources = [
     "web/WindowFeaturesStructTraits.cpp",
   ]
   deps = [
     ":new_wrapper_types_mojo_bindings_shared__generator",
   ]
 }