DevTools: Remove unused CodeMirrorCSSLoadView

This code was not used

Change-Id: I57c742e34811807e091d8a833fa89ac0487e64bf
Reviewed-on: https://chromium-review.googlesource.com/c/1356128Reviewed-by: Dmitry Gozman <dgozman@chromium.org>
Commit-Queue: Joel Einbinder <einbinder@chromium.org>
Cr-Commit-Position: refs/heads/master@{#612771}

third_party/blink/renderer/devtools/front_end/text_editor/CodeMirrorUtils.js

@@ -153,19 +153,3 @@ TextEditor.CodeMirrorUtils.TokenizerFactory = class {
     return tokenize;
   }
 };
-
-/**
- * @unrestricted
- */
-TextEditor.CodeMirrorCSSLoadView = class extends UI.VBox {
-  /**
-   * This bogus view is needed to load/unload CodeMirror-related CSS on demand.
-   */
-  constructor() {
-    super();
-    this.element.classList.add('hidden');
-    this.registerRequiredCSS('cm/codemirror.css');
-    this.registerRequiredCSS('text_editor/cmdevtools.css');
-    TextEditor.CodeMirrorUtils.appendThemeStyle(this.element);
-  }
-};