PasswordStore: Clean up expectations about rewriting vectors of forms

chrome/browser/password_manager/password_store_mac.cc

Index: chrome/browser/password_manager/password_store_mac.cc
diff --git a/chrome/browser/password_manager/password_store_mac.cc b/chrome/browser/password_manager/password_store_mac.cc
index 31c0d2b43d67d07a11c33b539ebc98d31deac799..51f2ad11a5a5969bb50358b868c5f5e579fe2ef8 100644
--- a/chrome/browser/password_manager/password_store_mac.cc
+++ b/chrome/browser/password_manager/password_store_mac.cc
@@ -1062,11 +1062,11 @@ ScopedVector<autofill::PasswordForm> PasswordStoreMac::FillMatchingLogins(
   chrome::ScopedSecKeychainSetUserInteractionAllowed user_interaction_allowed(
       prompt_policy == ALLOW_PROMPT);
 
-  if (!login_metadata_db_)
-    return ScopedVector<autofill::PasswordForm>();
-
   ScopedVector<PasswordForm> database_forms;
-  login_metadata_db_->GetLogins(form, &database_forms);
+  if (!login_metadata_db_ ||
+      !login_metadata_db_->GetLogins(form, &database_forms)) {
+    return ScopedVector<autofill::PasswordForm>();
+  }
 
   // Let's gather all signon realms we want to match with keychain entries.
   std::set<std::string> realm_set;
@@ -1125,6 +1125,7 @@ void PasswordStoreMac::GetAutofillableLoginsImpl(
 bool PasswordStoreMac::FillAutofillableLogins(
     ScopedVector<autofill::PasswordForm>* forms) {
   DCHECK(thread_->message_loop() == base::MessageLoop::current());
+  forms->clear();
 
   ScopedVector<PasswordForm> database_forms;
   if (!login_metadata_db_ ||
@@ -1144,6 +1145,7 @@ bool PasswordStoreMac::FillAutofillableLogins(
 
 bool PasswordStoreMac::FillBlacklistLogins(
     ScopedVector<autofill::PasswordForm>* forms) {
+  forms->clear();

[engedy, 2015/03/09 13:33:18]

nit: Sorry, I was meaning to say after the DCHECK. This looks weird. :)

[vabr (Chromium), 2015/03/09 17:44:15]

Done.
I agree that preconditions-checking DCHECK should be the first line, I should
have looked more carefully.

   DCHECK(thread_->message_loop() == base::MessageLoop::current());
   return login_metadata_db_ && login_metadata_db_->GetBlacklistLogins(forms);
 }
@@ -1161,7 +1163,8 @@ bool PasswordStoreMac::DatabaseHasFormMatchingKeychainForm(
   DCHECK(login_metadata_db_);
   bool has_match = false;
   ScopedVector<autofill::PasswordForm> database_forms;
-  login_metadata_db_->GetLogins(form, &database_forms);
+  if (!login_metadata_db_->GetLogins(form, &database_forms))
+    return false;
   for (const autofill::PasswordForm* db_form : database_forms) {
     // Below we filter out forms with non-empty original_signon_realm, because
     // those signal fuzzy matches, and we are only interested in exact ones.
@@ -1204,7 +1207,8 @@ void PasswordStoreMac::CleanOrphanedForms(
   DCHECK(login_metadata_db_);
 
   ScopedVector<autofill::PasswordForm> database_forms;
-  login_metadata_db_->GetAutofillableLogins(&database_forms);
+  if (!login_metadata_db_->GetAutofillableLogins(&database_forms))
+    return;
 
   // Filter forms with corresponding Keychain entry out of |database_forms|.
   ScopedVector<PasswordForm> forms_with_keychain_entry;