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

content/content_common_mojo_bindings.gyp

Index: content/content_common_mojo_bindings.gyp
diff --git a/content/content_common_mojo_bindings.gyp b/content/content_common_mojo_bindings.gyp
index 8f0a5eb1fb7ecd6ada17321a38e1c2b06ff570e0..1f29500c9569540bbb260a7ec7f3b1016ca5ae5d 100644
--- a/content/content_common_mojo_bindings.gyp
+++ b/content/content_common_mojo_bindings.gyp
@@ -12,7 +12,6 @@
         'mojom_files': [
           # NOTE: Sources duplicated in //content/common/BUILD.gn:mojo_bindings.
           'common/application_setup.mojom',
-          'common/background_sync_service.mojom',
           'common/image_downloader/image_downloader.mojom',
           'common/leveldb_wrapper.mojom',
           'common/presentation/presentation_service.mojom',
@@ -20,11 +19,6 @@
           'common/render_frame_setup.mojom',
           'common/service_worker/embedded_worker_setup.mojom',
           'common/storage_partition_service.mojom',
-
-          # NOTE: Sources duplicated in
-          # //content/public/common/BUILD.gn:mojo_bindings.
-          'public/common/background_sync.mojom',
-          'public/common/service_worker_event_status.mojom',
         ],
         'mojom_typemaps': [
           '../url/mojo/gurl.typemap',