Automated Drupal 9 compatibility fixes

I have added a patch for Drupal 9 compatibility of this module.

I'm getting another Drupal 9 issue. To be clear, this module worked fine in Drupal 8.

I created another ticket for this: https://www.drupal.org/project/admin_toolbar_toggle/issues/3167322

The website encountered an unexpected error. Please try again later.

Drupal\Core\Security\UntrustedCallbackException: Render #pre_render callbacks must be methods of a class that implements \Drupal\Core\Security\TrustedCallbackInterface or be an anonymous function. The callback was _admin_toolbar_toggle_pre_render_toolbar. See https://www.drupal.org/node/2966725 in Drupal\Core\Render\Renderer->doTrustedCallback() (line 96 of core/lib/Drupal/Core/Security/DoTrustedCallbackTrait.php).
Drupal\Core\Render\Renderer->doCallback('#pre_render', '_admin_toolbar_toggle_pre_render_toolbar', Array) (Line: 372)
Drupal\Core\Render\Renderer->doRender(Array) (Line: 444)
Drupal\Core\Render\Renderer->doRender(Array, ) (Line: 200)
Drupal\Core\Render\Renderer->render(Array) (Line: 450)
Drupal\Core\Template\TwigExtension->escapeFilter(Object, Array, 'html', NULL, 1) (Line: 105)
__TwigTemplate_1f57c2b3c5e0f470df2ec7e1bea1bd707d248aa3ad39b428f22e887c70d843cb->doDisplay(Array, Array) (Line: 407)
Twig\Template->displayWithErrorHandling(Array, Array) (Line: 380)
Twig\Template->display(Array) (Line: 392)
Twig\Template->render(Array) (Line: 65)
twig_render_template('core/themes/seven/templates/classy/layout/html.html.twig', Array) (Line: 384)
Drupal\Core\Theme\ThemeManager->render('html', Array) (Line: 431)
Drupal\Core\Render\Renderer->doRender(Array, ) (Line: 200)
Drupal\Core\Render\Renderer->render(Array) (Line: 147)
Drupal\Core\Render\MainContent\HtmlRenderer->Drupal\Core\Render\MainContent\{closure}() (Line: 573)
Drupal\Core\Render\Renderer->executeInRenderContext(Object, Object) (Line: 148)
Drupal\Core\Render\MainContent\HtmlRenderer->renderResponse(Array, Object, Object) (Line: 90)
Drupal\Core\EventSubscriber\MainContentViewSubscriber->onViewRenderArray(Object, 'kernel.view', Object) (Line: 78)
Symfony\Component\EventDispatcher\LegacyEventDispatcherProxy->dispatch(Object, 'kernel.view') (Line: 163)
Symfony\Component\HttpKernel\HttpKernel->handleRaw(Object, 1) (Line: 80)
Symfony\Component\HttpKernel\HttpKernel->handle(Object, 1, 1) (Line: 57)
Drupal\Core\StackMiddleware\Session->handle(Object, 1, 1) (Line: 47)
Drupal\Core\StackMiddleware\KernelPreHandle->handle(Object, 1, 1) (Line: 106)
Drupal\page_cache\StackMiddleware\PageCache->pass(Object, 1, 1) (Line: 85)
Drupal\page_cache\StackMiddleware\PageCache->handle(Object, 1, 1) (Line: 50)
Drupal\ban\BanMiddleware->handle(Object, 1, 1) (Line: 47)
Drupal\Core\StackMiddleware\ReverseProxyMiddleware->handle(Object, 1, 1) (Line: 52)
Drupal\Core\StackMiddleware\NegotiationMiddleware->handle(Object, 1, 1) (Line: 23)
Stack\StackedHttpKernel->handle(Object, 1, 1) (Line: 705)
Drupal\Core\DrupalKernel->handle(Object) (Line: 19)

@deepakkumar14 - there does not seem to be much activity on this module, but I cannot find any other recent modules doing something similar. I tried to fix this myself, but only succeeded at making the menu disappear completely. While it doesn't seem like a complex module, I can't figure out how to fix the code. I understand that in Drupal 9, the callback is supposed to be in a class that implements TrustedCallbackInterface. Can you help finish making this Drupal 9 compatible? It would be greatly appreciated.

This patch incorporates the previous fixes and moves the #pre_render callback function into a class that implements TrustedCallbackInterface.

Here is the relevant change record for this: https://www.drupal.org/node/2966725.

@deepakkumar14 thanks for kicking this off, and @jasonluttrell thanks for reporting the other issue. I think we should close that one and call it fixed in here if this patch passes review.

Changing the line to:

$info['toolbar']['#pre_render'][] = [\Drupal\admin_toolbar_toggle\AdminToolbarToggle::class, 'preRender'];

Excellent. Thanks for the work on this! I tried out the patch in #7 on my local computer and it works wonderfully.