Move device/core files to device/base directory.

device/usb/mojo/BUILD.gn

 # Copyright 2016 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.
 
 source_set("mojo") {
   sources = [
     "device_impl.cc",
     "device_impl.h",
     "device_manager_impl.cc",
     "device_manager_impl.h",
     "permission_provider.cc",
     "permission_provider.h",
     "type_converters.cc",
     "type_converters.h",
   ]
 
   deps = [
-    "//device/core",
+    "//device/base",
     "//device/usb",
     "//device/usb/public/interfaces",
     "//mojo/common",
     "//mojo/public/cpp/bindings",
     "//net",
   ]
 }