Update GN build files for new prefs location.

components/sync_sessions/BUILD.gn

 # Copyright 2015 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: components/sync_sessions.gypi:sync_sessions
 source_set("sync_sessions") {
   sources = [
     "favicon_cache.cc",
     "favicon_cache.h",
     "local_session_event_router.h",
@@ skipping 31 matching lines @@
     "synced_tab_delegate.h",
     "synced_window_delegate.h",
     "synced_window_delegates_getter.cc",
     "synced_window_delegates_getter.h",
     "tab_node_pool.cc",
     "tab_node_pool.h",
   ]
 
   deps = [
     "//base",
-    "//base:prefs",
     "//components/bookmarks/browser",
     "//components/favicon/core",
     "//components/history/core/browser",
+    "//components/prefs",
     "//components/sessions",
     "//components/sync_driver",
     "//components/variations",
     "//sync",
     "//ui/base:base",
     "//ui/gfx",
     "//url",
   ]
 }
 
@@ skipping 24 matching lines @@
     "revisit/sessions_page_revisit_observer_unittest.cc",
     "revisit/typed_url_page_revisit_task_unittest.cc",
     "session_data_type_controller_unittest.cc",
     "synced_session_tracker_unittest.cc",
     "tab_node_pool_unittest.cc",
   ]
 
   deps = [
     ":sync_sessions",
     ":test_support",
-    "//base:prefs",
-    "//base:prefs_test_support",
     "//base/test:test_support",
     "//components/bookmarks/browser",
     "//components/history/core/browser",
+    "//components/prefs:test_support",
     "//components/sessions:test_support",
     "//components/sync_driver",
     "//components/sync_driver:test_support",
     "//sync",
     "//sync:test_support_sync_api",
     "//testing/gmock",
     "//testing/gtest",
     "//ui/base:base",
     "//url",
   ]
 }