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

content/public/browser/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("//content/browser/browser.gni")
 import("//build/config/ui.gni")
 
 # See //content/BUILD.gn for how this works.
 group("browser") {
   if (is_component_build) {
@@ skipping 14 matching lines @@
   sources = rebase_path(content_browser_gypi_values.public_browser_sources,
                         ".",
                         "//content")
 
   configs += [
     "//build/config:precompiled_headers",
     "//content:content_implementation",
   ]
 
   public_deps = [
-    "//content/public/common:mojo_bindings",
     "//mojo/public/cpp/bindings",
     "//mojo/public/cpp/system",
 
     # We expose skia headers in the public API.
     "//skia",
+    "//third_party/WebKit/public:mojo_bindings",
   ]
   deps = [
     "//cc",
     "//content/browser",  # Must not be public_deps!
     "//content/public/common:common_sources",
     "//gpu",
     "//media",
     "//net",
     "//ppapi/c",
     "//storage/browser",
@@ skipping 12 matching lines @@
 
   if (is_android) {
     deps += [ "//ui/android" ]
   }
 
   if (use_aura) {
     sources -= [ "context_factory.h" ]
     deps += [ "//ui/aura" ]
   }
 }