Clean up code to delete the passwords account store if feature disabled

Before this CL, there was some code running on browser startup that'd
delete the account-scoped password store if the corresponding feature
flag is disabled.
That feature flag is fully launched now, so no more need for the cleanup
code.

This basically reverts crrev.com/c/2300439 and crrev.com/c/2320278,
plus adds pref cleanup logic.

Bug: 1108738
Change-Id: Ie54145bc6f2c0d7d5903b2880f056e6979134f27
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/3056006
Commit-Queue: Marc Treib <[email protected]>
Reviewed-by: Mohamed Amir Yosef <[email protected]>
Cr-Commit-Position: refs/heads/master@{#906101}
diff --git a/chrome/browser/prefs/browser_prefs.cc b/chrome/browser/prefs/browser_prefs.cc
index 1370d13..d3be33e 100644
--- a/chrome/browser/prefs/browser_prefs.cc
+++ b/chrome/browser/prefs/browser_prefs.cc
@@ -654,6 +654,9 @@
     "printing.force_enable_privet_printing";
 #endif
 
+// Deprecated 07/2021.
+const char kAccountStorageExists[] = "profile.password_account_storage_exists";
+
 // Register local state used only for migration (clearing or moving to a new
 // key).
 void RegisterLocalStatePrefsForMigration(PrefRegistrySimple* registry) {
@@ -846,6 +849,8 @@
                                 false);
   registry->RegisterBooleanPref(kForceEnablePrivetPrinting, false);
 #endif
+
+  registry->RegisterBooleanPref(kAccountStorageExists, false);
 }
 
 }  // namespace
@@ -1651,6 +1656,9 @@
   profile_prefs->ClearPref(kForceEnablePrivetPrinting);
 #endif
 
+  // Added 2021/07.
+  profile_prefs->ClearPref(kAccountStorageExists);
+
   // Please don't delete the following line. It is used by PRESUBMIT.py.
   // END_MIGRATE_OBSOLETE_PROFILE_PREFS
 }