Remove old default search preferences.

chrome/browser/prefs/chrome_pref_service_factory.cc

Index: chrome/browser/prefs/chrome_pref_service_factory.cc
diff --git a/chrome/browser/prefs/chrome_pref_service_factory.cc b/chrome/browser/prefs/chrome_pref_service_factory.cc
index 0b72728a91612c7990959c6aec2034f5e6d2d236..df2ebdae73c3f208c94214c8d44c663ae1b147be 100644
--- a/chrome/browser/prefs/chrome_pref_service_factory.cc
+++ b/chrome/browser/prefs/chrome_pref_service_factory.cc
@@ -47,7 +47,6 @@
 #include "components/prefs/pref_store.h"
 #include "components/prefs/pref_value_store.h"
 #include "components/search_engines/default_search_manager.h"
-#include "components/search_engines/default_search_pref_migration.h"
 #include "components/search_engines/search_engines_pref_names.h"
 #include "components/signin/core/common/signin_pref_names.h"
 #include "components/sync/base/model_type.h"
@@ -147,18 +146,21 @@ const PrefHashFilter::TrackedPreferenceMetadata kTrackedPrefs[] = {
     PrefHashFilter::TRACKING_STRATEGY_ATOMIC,
     PrefHashFilter::VALUE_IMPERSONAL
   },
+  // Deprecated, will be removed several releases after M57.
   {
     8, prefs::kDefaultSearchProviderSearchURL,

[gab, 2016/12/23 17:26:26]

If they're no longer migrated, why do they still need to be protected? Feels we
should outright delete kDefaultSearchProviderSearchURL (we usually have a
cleanup phase in browser_prefs.cc::MigrateUserPrefs() for a year but it's
unecessary here given the preceding migration having the same effect -- i.e.
ClearDefaultSearchProviderFromLegacyPrefs()).

[Alexander Yashkin, 2016/12/23 20:28:13]

Done

     PrefHashFilter::ENFORCE_ON_LOAD,
     PrefHashFilter::TRACKING_STRATEGY_ATOMIC,
     PrefHashFilter::VALUE_IMPERSONAL
   },
+  // Deprecated, will be removed several releases after M57.
   {
     9, prefs::kDefaultSearchProviderKeyword,
     PrefHashFilter::ENFORCE_ON_LOAD,
     PrefHashFilter::TRACKING_STRATEGY_ATOMIC,
     PrefHashFilter::VALUE_IMPERSONAL
   },
+  // Deprecated, will be removed several releases after M57.
   {
     10, prefs::kDefaultSearchProviderName,
     PrefHashFilter::ENFORCE_ON_LOAD,
@@ -518,8 +520,6 @@ std::unique_ptr<sync_preferences::PrefServiceSyncable> CreateProfilePrefs(
   std::unique_ptr<sync_preferences::PrefServiceSyncable> pref_service =
       factory.CreateSyncable(pref_registry.get());
 
-  ConfigureDefaultSearchPrefMigrationToDictionaryValue(pref_service.get());
-
   return pref_service;
 }