Augment PrefHashFilter with the ability to cleanup deprecated tracked preferences and their matching MAC.

The time has come where some tracked preferences are starting to be deprecated and keeping them declared
solely for the sake of having them migrated back to the unprotected store by TrackedPreferencesMigrator
only to be cleared from that store shortly after is adding overhead (and furthermore with that technique
only the value would be cleaned up, not its matching MAC).

Implemented in CleanupDeprecatedTrackedPreferences() in pref_hash_filter.cc and added a comment pointing
to it from kTrackedPrefs.

Review URL: https://codereview.chromium.org/432533003

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@287050 0039d316-1c4b-4281-b951-d872f2087c98

3 files changed, 0 insertions, 11 deletions

diff --git a/extensions/browser/extension_prefs.cc b/extensions/browser/extension_prefs.cc
index efe3ba4..502816c 100644
--- a/extensions/browser/extension_prefs.cc
+++ b/extensions/browser/extension_prefs.cc
@@ -1920,10 +1920,6 @@ ExtensionPrefs::ExtensionPrefs(
       app_sorting_(app_sorting.Pass()),
       time_provider_(time_provider.Pass()),
       extensions_disabled_(extensions_disabled) {
-  // Remove this deprecated pref.
-  // TODO(gab): Remove the pref's name from the code base altogether in M40.
-  prefs_->ClearPref(pref_names::kKnownDisabled);
-
   app_sorting_->SetExtensionScopedPrefs(this);
   MakePathsRelative();
 
@@ -1988,8 +1984,6 @@ void ExtensionPrefs::RegisterProfilePrefs(
       pref_names::kLastChromeVersion,
       std::string(),  // default value
       user_prefs::PrefRegistrySyncable::UNSYNCABLE_PREF);
-  registry->RegisterListPref(pref_names::kKnownDisabled,
-                             user_prefs::PrefRegistrySyncable::UNSYNCABLE_PREF);
 #if defined(OS_MACOSX)
   registry->RegisterDoublePref(
       pref_names::kBrowserActionContainerWidth,
diff --git a/extensions/browser/pref_names.cc b/extensions/browser/pref_names.cc
index 76a7dc1..b693d21 100644
--- a/extensions/browser/pref_names.cc
+++ b/extensions/browser/pref_names.cc
@@ -38,7 +38,6 @@ const char kExtensions[] = "extensions.settings";
 const char kInstallAllowList[] = "extensions.install.allowlist";
 const char kInstallDenyList[] = "extensions.install.denylist";
 const char kInstallForceList[] = "extensions.install.forcelist";
-const char kKnownDisabled[] = "extensions.known_disabled";
 const char kLastChromeVersion[] = "extensions.last_chrome_version";
 const char kLastUpdateCheck[] = "extensions.autoupdate.last_check";
 const char kNativeMessagingBlacklist[] = "native_messaging.blacklist";
diff --git a/extensions/browser/pref_names.h b/extensions/browser/pref_names.h
index 4f64677..131a939 100644
--- a/extensions/browser/pref_names.h
+++ b/extensions/browser/pref_names.h
@@ -64,10 +64,6 @@ extern const char kInstallDenyList[];
 // accessed through extensions::ExternalPolicyProvider.
 extern const char kInstallForceList[];
 
-// Deprecated. A list of known disabled extensions IDs.
-// TODO(gab): Remove this pref in M40+.
-extern const char kKnownDisabled[];
-
 // String pref for what version chrome was last time the extension prefs were
 // loaded.
 extern const char kLastChromeVersion[];