[Invalidations] Remove unique owner name feature.

The kInvalidatorUniqueOwnerName feature was enabled for device since
M90. By now most of devices are expected to migrate to new owner names
so traffic for redundant re-subscriptions should be minimal (or none).
So it is safe to drop the feature flag.

Additionally, add pref cleanup for topics with old Cloud owner/handler
names. There's non-zero possibility that topics were saved with old
owner name but never re-registered with a new one. Clear pref from such
records.

Additionally, remove OwnerNameToHandlerType function as it never used.
HandlerOwnerType is not used as well, but kept for compatibility with
enums.xml.

Bug: chromium:1049591
Test: components_unittests --gtest_filter="InvalidatorRegistrarWithMemoryTest*"
Change-Id: I76f9548455e3c23a9f178a5369ef230dd15d2422
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/3412041
Reviewed-by: Gabriel Charette <[email protected]>
Reviewed-by: Marc Treib <[email protected]>
Reviewed-by: Roman Sorokin <[email protected]>
Commit-Queue: Artem Sumaneev <[email protected]>
Cr-Commit-Position: refs/heads/main@{#965258}
diff --git a/chrome/browser/prefs/browser_prefs.cc b/chrome/browser/prefs/browser_prefs.cc
index 13071fe..6d1fae9 100644
--- a/chrome/browser/prefs/browser_prefs.cc
+++ b/chrome/browser/prefs/browser_prefs.cc
@@ -1622,6 +1622,10 @@
   local_state->ClearPref(kStabilityIncompleteSessionEndCount);
   local_state->ClearPref(kStabilitySessionEndCompleted);
 
+  // Added 01/2022.
+  invalidation::InvalidatorRegistrarWithMemory::
+      ClearTopicsWithObsoleteOwnerNames(local_state);
+
   // Please don't delete the following line. It is used by PRESUBMIT.py.
   // END_MIGRATE_OBSOLETE_LOCAL_STATE_PREFS
 }
@@ -1888,6 +1892,10 @@
   profile_prefs->ClearPref(kThisWeekUserTrafficContentTypeDownstreamKB);
   profile_prefs->ClearPref(kLastWeekUserTrafficContentTypeDownstreamKB);
 
+  // Added 01/2022.
+  invalidation::InvalidatorRegistrarWithMemory::
+      ClearTopicsWithObsoleteOwnerNames(profile_prefs);
+
   // Please don't delete the following line. It is used by PRESUBMIT.py.
   // END_MIGRATE_OBSOLETE_PROFILE_PREFS
 }