Move webpreferences.* from webkit/ to content/

webkit/common/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.
 
 # GYP version: webkit/common/webkit_common.gyp:webkit_common
 component("common") {
   output_name = "webkit_common"
 
   sources = [
     "data_element.cc",
     "data_element.h",
     "webkit_common_export.h",
-    "webpreferences.cc",
-    "webpreferences.h",
   ]
 
   defines = [ "WEBKIT_COMMON_IMPLEMENTATION" ]
 
   deps = [
     "//base",
     "//base:i18n",
     "//base/third_party/dynamic_annotations",
     "//net",
     "//skia",
@@ skipping 44 matching lines @@
   }
 
   deps = [
     ":common",
     "//base",
     "//base/third_party/dynamic_annotations",
     "//net",
     "//url",
   ]
 }