Make sure that when a SupportsUserData is destroyed, objects destroyed transitively see it as empty.

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 1155 matching lines @@
     "strings/string_number_conversions_unittest.cc",
     "strings/string_piece_unittest.cc",
     "strings/string_split_unittest.cc",
     "strings/string_tokenizer_unittest.cc",
     "strings/string_util_unittest.cc",
     "strings/stringize_macros_unittest.cc",
     "strings/sys_string_conversions_mac_unittest.mm",
     "strings/sys_string_conversions_unittest.cc",
     "strings/utf_offset_string_conversions_unittest.cc",
     "strings/utf_string_conversions_unittest.cc",
+    "supports_user_data_unittest.cc",
     "sync_socket_unittest.cc",
     "synchronization/cancellation_flag_unittest.cc",
     "synchronization/condition_variable_unittest.cc",
     "synchronization/lock_unittest.cc",
     "synchronization/waitable_event_unittest.cc",
     "synchronization/waitable_event_watcher_unittest.cc",
     "sys_info_unittest.cc",
     "system_monitor/system_monitor_unittest.cc",
     "task/cancelable_task_tracker_unittest.cc",
     "task_runner_util_unittest.cc",
@@ skipping 163 matching lines @@
     source_prereqs = [
       "android/java/templates/native_libraries_array.h",
       ]
 
     package_name = "org/chromium/base/library_loader"
     include_path = "android/java/templates"
   }
 
 
 }