Fixes Microsoft/monaco-editor#425: Create an aria container dom node as soon...

Fixes Microsoft/monaco-editor#425: Create an aria container dom node as soon as the first editor is instantiated

src/vs/base/browser/ui/aria/aria.css

@@ -3,7 +3,7 @@
  *  Licensed under the MIT License. See License.txt in the project root for license information.
  *--------------------------------------------------------------------------------------------*/
 
-.aria-container {
+.monaco-aria-container {
 	position: absolute; /* try to hide from workbench but not from screen readers */
 	left:-999em;
 }
\ No newline at end of file

src/vs/base/browser/ui/aria/aria.ts

@@ -14,10 +14,10 @@ let ariaContainer: Builder;
 let alertContainer: Builder;
 let statusContainer: Builder;
 export function setARIAContainer(parent: HTMLElement) {
-	ariaContainer = $('.aria-container').appendTo(parent);
+	ariaContainer = $('.monaco-aria-container').appendTo(parent);
 
-	alertContainer = $('.alert').appendTo(ariaContainer).attr({ 'role': 'alert', 'aria-atomic': 'true' });
-	statusContainer = $('.status').appendTo(ariaContainer).attr({ 'role': 'status', 'aria-atomic': 'true' });
+	alertContainer = $('.monaco-alert').appendTo(ariaContainer).attr({ 'role': 'alert', 'aria-atomic': 'true' });
+	statusContainer = $('.monaco-status').appendTo(ariaContainer).attr({ 'role': 'status', 'aria-atomic': 'true' });
 }
 
 /**

src/vs/editor/browser/standalone/standaloneCodeEditor.ts

@@ -25,6 +25,7 @@ import { InternalEditorAction } from 'vs/editor/common/editorAction';
 import { MenuId, MenuRegistry, IMenuItem } from 'vs/platform/actions/common/actions';
 import { IDiffEditorOptions, IEditorOptions } from 'vs/editor/common/config/editorOptions';
 import { IThemeService } from 'vs/platform/theme/common/themeService';
+import * as aria from 'vs/base/browser/ui/aria/aria';
 
 /**
  * The options to create an editor.
@@ -83,6 +84,15 @@ export interface IStandaloneDiffEditor extends IDiffEditor {
 
 let LAST_GENERATED_COMMAND_ID = 0;
 
+let ariaDomNodeCreated = false;
+function createAriaDomNode() {
+	if (ariaDomNodeCreated) {
+		return;
+	}
+	ariaDomNodeCreated = true;
+	aria.setARIAContainer(document.body);
+}
+
 /**
  * A code editor to be used both by the standalone editor and the standalone diff editor.
  */
@@ -105,6 +115,9 @@ export class StandaloneCodeEditor extends CodeEditor implements IStandaloneCodeE
 		if (keybindingService instanceof StandaloneKeybindingService) {
 			this._standaloneKeybindingService = keybindingService;
 		}
+
+		// Create the ARIA dom node as soon as the first editor is instantiated
+		createAriaDomNode();
 	}
 
 	public addCommand(keybinding: number, handler: ICommandHandler, context: string): string {