Fix a useless DisallowTransitionScope in html_input_element.cc

It was introduced in I0ad30908e76a9084ba8d685285e613a7194c02fb, but without
giving it a name it just creates and destroys a temporary, which is useless.

Bug: 1009806
Change-Id: I900a4f652c1ef4233a182d69a742c5162479af72
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1863796
Auto-Submit: Emilio Cobos Álvarez <emilio@chromium.org>
Commit-Queue: Koji Ishii <kojii@chromium.org>
Reviewed-by: Koji Ishii <kojii@chromium.org>
Cr-Commit-Position: refs/heads/master@{#706392}

third_party/blink/renderer/core/html/forms/html_input_element.cc

@@ -416,7 +416,8 @@ void HTMLInputElement::UpdateType() {
   SetForceReattachLayoutTree();
 
   // In this function, we should not do force to do style recalc and layout.
-  DocumentLifecycle::DisallowTransitionScope(GetDocument().Lifecycle());
+  DocumentLifecycle::DisallowTransitionScope disallow_transition(
+      GetDocument().Lifecycle());
 
   if (input_type_->SupportsRequired() != new_type->SupportsRequired() &&
       IsRequired()) {