Open the LoginDatabase on the DB thread, not the UI thread.

components/password_manager/core/browser/login_database.cc

Index: components/password_manager/core/browser/login_database.cc
diff --git a/components/password_manager/core/browser/login_database.cc b/components/password_manager/core/browser/login_database.cc
index c769481f532e512111f025245528ba05d1549e89..0cf252c1089f981c70d7745301254040013406c8 100644
--- a/components/password_manager/core/browser/login_database.cc
+++ b/components/password_manager/core/browser/login_database.cc
@@ -154,6 +154,9 @@ void LogTimesUsedStat(const std::string& name, int sample) {
   LogDynamicUMAStat(name, sample, 0, 100, 10);
 }
 
+// When set, LoginDatabase::Init() on any instance will artificially fail.
+bool g_simulate_init_failure_for_testing = false;
+
 }  // namespace
 
 LoginDatabase::LoginDatabase() {
@@ -163,6 +166,9 @@ LoginDatabase::~LoginDatabase() {
 }
 
 bool LoginDatabase::Init(const base::FilePath& db_path) {
+  if (g_simulate_init_failure_for_testing)
+    return false;
+
   // Set pragmas for a small, private database (based on WebDatabase).
   db_.set_page_size(2048);
   db_.set_cache_size(32);
@@ -440,6 +446,11 @@ void LoginDatabase::ReportMetrics(const std::string& sync_username,
                             4);
 }
 
+// static
+void LoginDatabase::set_simulate_init_failure_for_testing(bool fail) {
+  g_simulate_init_failure_for_testing = fail;
+}
+
 PasswordStoreChangeList LoginDatabase::AddLogin(const PasswordForm& form) {
   PasswordStoreChangeList list;
   if (!DoesMatchConstraints(form))