GN: Move mock_pref_change_callback.h to the correct section.

base/BUILD.gn

 # Copyright (c) 2013 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("//build/config/android/rules.gni")
 import("//build/config/ui.gni")
 
 component("base") {
   sources = [
     "third_party/dmg_fp/dmg_fp.h",
@@ skipping 971 matching lines @@
   ]
 
   defines = [ "BASE_PREFS_IMPLEMENTATION" ]
 
   deps = [ ":base" ]
 }
 
 source_set("prefs_test_support") {
   sources = [
     "prefs/mock_pref_change_callback.cc",
+    "prefs/mock_pref_change_callback.h",
     "prefs/pref_store_observer_mock.cc",
     "prefs/pref_store_observer_mock.h",
     "prefs/testing_pref_service.cc",
     "prefs/testing_pref_service.h",
     "prefs/testing_pref_store.cc",
     "prefs/testing_pref_store.h",
   ]
 
   deps = [
     ":base",
@@ skipping 131 matching lines @@
     "metrics/statistics_recorder_unittest.cc",
     "observer_list_unittest.cc",
     "os_compat_android_unittest.cc",
     "path_service_unittest.cc",
     "pickle_unittest.cc",
     "posix/file_descriptor_shuffle_unittest.cc",
     "posix/unix_domain_socket_linux_unittest.cc",
     "power_monitor/power_monitor_unittest.cc",
     "prefs/default_pref_store_unittest.cc",
     "prefs/json_pref_store_unittest.cc",
-    "prefs/mock_pref_change_callback.h",
     "prefs/overlay_user_pref_store_unittest.cc",
     "prefs/pref_change_registrar_unittest.cc",
     "prefs/pref_member_unittest.cc",
     "prefs/pref_notifier_impl_unittest.cc",
     "prefs/pref_service_unittest.cc",
     "prefs/pref_value_map_unittest.cc",
     "prefs/pref_value_store_unittest.cc",
     "prefs/scoped_user_pref_update_unittest.cc",
     "process/memory_unittest.cc",
     "process/memory_unittest_mac.h",
@@ skipping 259 matching lines @@
       "android/java/templates/NativeLibraries.template",
       ]
     source_prereqs = [
       "android/java/templates/native_libraries_array.h",
       ]
 
     package_name = "org/chromium/base/library_loader"
     include_path = "android/java/templates"
   }
 }