Move kDataReductionProxy registration to the data_reduction_proxy component.

ios/chrome/browser/prefs/browser_prefs.mm

 // 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.
 
 #include "ios/chrome/browser/prefs/browser_prefs.h"
 
 #include "base/prefs/pref_service.h"
 #include "components/autofill/core/browser/autofill_manager.h"
 #include "components/content_settings/core/browser/host_content_settings_map.h"
 #include "components/data_reduction_proxy/core/browser/data_reduction_proxy_prefs.h"
-#include "components/data_reduction_proxy/core/common/data_reduction_proxy_pref_names.h"
 #include "components/dom_distiller/core/distilled_page_prefs.h"
 #include "components/enhanced_bookmarks/bookmark_server_cluster_service.h"
 #include "components/gcm_driver/gcm_channel_status_syncer.h"
 #include "components/network_time/network_time_tracker.h"
 #include "components/omnibox/browser/zero_suggest_provider.h"
 #include "components/password_manager/core/browser/password_manager.h"
 #include "components/pref_registry/pref_registry_syncable.h"
 #include "components/proxy_config/pref_proxy_config_tracker_impl.h"
 #include "components/rappor/rappor_service.h"
 #include "components/search_engines/template_url_prepopulate_data.h"
@@ skipping 38 matching lines @@
 
   // Preferences related to the browser state manager.
   registry->RegisterStringPref(ios::prefs::kBrowserStateLastUsed,
                                std::string());
   registry->RegisterIntegerPref(ios::prefs::kBrowserStatesNumCreated, 1);
   registry->RegisterListPref(ios::prefs::kBrowserStatesLastActive);
 
   [OmniboxGeolocationLocalState registerLocalState:registry];
   [MemoryDebuggerManager registerLocalState:registry];
 
-  // TODO(crbug.com/557814): data_reduction_proxy::prefs::kDataReductionProxy
-  // should be registered by data_reduction_proxy::RegisterPrefs() instead of
-  // here.
-  registry->RegisterStringPref(data_reduction_proxy::prefs::kDataReductionProxy,
-                               std::string());
   data_reduction_proxy::RegisterPrefs(registry);
 
   // TODO(shreyasv): Remove this in M49 as almost all users would have the
   // "do not backup" bit set by then. crbug.com/489865.
   registry->RegisterBooleanPref(prefs::kOTRStashStatePathSystemBackupExcluded,
                                 false);
   registry->RegisterBooleanPref(prefs::kBrowsingDataMigrationHasBeenPossible,
                                 false);
 
   ApplicationContextImpl::RegisterPrefs(registry);
@@ skipping 55 matching lines @@
 
 // This method should be periodically pruned of year+ old migrations.
 void MigrateObsoleteBrowserStatePrefs(PrefService* prefs) {
   // Added 07/2014.
   translate::TranslatePrefs::MigrateUserPrefs(prefs,
                                               ios::prefs::kAcceptLanguages);
 
   // Added 08/2015.
   prefs->ClearPref(::prefs::kSigninSharedAuthenticationUserId);
 }