mac: Don't show keychain prompt for password Autofill.

components/password_manager/core/browser/password_manager.cc

Index: components/password_manager/core/browser/password_manager.cc
diff --git a/components/password_manager/core/browser/password_manager.cc b/components/password_manager/core/browser/password_manager.cc
index 7ef733bc445ab61e2d52c0b56e2752c298ac6576..2561ad0dc0939c576ba3d0271d9a80ec7b5c91bf 100644
--- a/components/password_manager/core/browser/password_manager.cc
+++ b/components/password_manager/core/browser/password_manager.cc
@@ -373,11 +373,18 @@ void PasswordManager::CreatePendingLoginManagers(
         new PasswordFormManager(this, client_, driver_, *iter, ssl_valid);
     pending_login_managers_.push_back(manager);
 
-    // Avoid prompting the user for access to a password if they don't have
-    // password saving enabled.
+    // Password Autofill is supposed to be a convenience. If it creates a
+    // blocking dialog, it is no longer convenient. We should only prompt the
+    // user after a full username has been typed in. Until that behavior is
+    // implemented, never prompt the user for keychain access.
+    // Effectively, this means that passwords stored by Chrome still work,
+    // since Chrome can access those without a prompt, but passwords stored by
+    // Safari, Firefox, or Chrome Canary will not work. Note that the latest
+    // build of Safari and Firefox don't create keychain items with the
+    // relevant tags anyways (7/11/2014).
+    // http://crbug.com/178358
     PasswordStore::AuthorizationPromptPolicy prompt_policy =
-        *saving_passwords_enabled_ ? PasswordStore::ALLOW_PROMPT
-                                   : PasswordStore::DISALLOW_PROMPT;
+        PasswordStore::DISALLOW_PROMPT;
 
     manager->FetchMatchingLoginsFromPasswordStore(prompt_policy);
   }