Putting histogram names of tracked prefs in tracked_preference_histogram_name file.

components/user_prefs/tracked/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.
 
 static_library("user_prefs_tracked") {
   sources = [
     "device_id.h",
     "device_id_mac.cc",
     "device_id_stub.cc",
     "device_id_win.cc",
@@ skipping 14 matching lines @@
     "pref_names.h",
     "pref_service_hash_store_contents.cc",
     "pref_service_hash_store_contents.h",
     "segregated_pref_store.cc",
     "segregated_pref_store.h",
     "tracked_atomic_preference.cc",
     "tracked_atomic_preference.h",
     "tracked_preference.h",
     "tracked_preference_helper.cc",
     "tracked_preference_helper.h",
+    "tracked_preference_histogram_names.cc",
+    "tracked_preference_histogram_names.h",
     "tracked_preference_validation_delegate.h",
     "tracked_preferences_migration.cc",
     "tracked_preferences_migration.h",
     "tracked_split_preference.cc",
     "tracked_split_preference.h",
   ]
 
   if (is_win || (is_mac && !is_ios)) {
     sources -= [ "device_id_stub.cc" ]
   }
@@ skipping 40 matching lines @@
 
   deps = [
     ":user_prefs_tracked",
     ":user_prefs_tracked_test_support",
     "//base:base",
     "//base:prefs",
     "//base:prefs_test_support",
     "//testing/gtest",
   ]
 }