Use ModuleHander::getName() instead of rebuilding module data on permissions page

Minor nitpick:

+++ b/core/modules/user/src/Form/UserPermissionsForm.php
@@ -41,9 +49,10 @@ class UserPermissionsForm extends FormBase {
+  public function __construct(PermissionHandlerInterface $permission_handler, RoleStorageInterface $role_storage, ModuleHandler $module_handler) {

Needs @param docblock

Nice find, we didn't see this one when improving getName() because it didn't call system_get_info()...

Testing this with the following in index.php, on an beta8 installation with a fair amount of roles and permissions and 215 non-test-folder .info.yml files (core as 74).

$start = microtime(TRUE);

print format_size(memory_get_peak_usage()) . "<br />\n";
print format_size(memory_get_usage()) . "<br />\n";
print round((microtime(TRUE) - $start), 2). "s";

This isn't too exact, since I also had to apply the patch from #2281989: Add a fast and simple way to get module name from the module handler, but it makes a nice difference for me:

Before:

167.32 MB
115.23 MB
15.8s

After:

133.27 MB
81.36 MB
11.09s (varies between 10-12s)

This is with xdebug and xhprof disabled. execution time varies quite a bit, but the memory numbers are stable.

Setting to needs work for the following nitpick:

+++ b/core/modules/user/src/Form/UserPermissionsForm.php
@@ -34,16 +35,26 @@ class UserPermissionsForm extends FormBase {
-  public function __construct(PermissionHandlerInterface $permission_handler, RoleStorageInterface $role_storage) {
+  public function __construct(PermissionHandlerInterface $permission_handler, RoleStorageInterface $role_storage, ModuleHandler $module_handler) {

type hint should be ModuleHandlerInterface (docs are correct).

Looks good to me :)

Looks great.

This issue addresses a major bug and is allowed per https://www.drupal.org/core/beta-changes. Committed 241def3 and pushed to 8.0.x. Thanks!