DevTools: Fix missing braces for a single line if statement

Change-Id: Ie80d2017d76133359eedf50218a88fe60266c6a3
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1854788Reviewed-by: Lorne Mitchell <lomitch@microsoft.com>
Commit-Queue: Mandy Chen <mandy.chen@microsoft.com>
Cr-Commit-Position: refs/heads/master@{#704960}

third_party/blink/renderer/devtools/front_end/ui/Toolbar.js

@@ -570,8 +570,9 @@ export class ToolbarButton extends ToolbarItem {
    * @param {!Event} event
    */
   _keydown(event) {
-    if (!this._enabled)
+    if (!this._enabled) {
       return;
+    }
     this.dispatchEventToListeners(UI.ToolbarButton.Events.KeyDown, event);
     event.consume();
   }