src/vs/workbench/api/browser/mainThreadEditors.ts/MainThreadTextEditors/$registerTextEditorDecorationType
class MainThreadTextEditors:	$registerTextEditorDecorationType(extensionId: ExtensionIdentifier, key: string, options: IDecorationRenderOptions): void {
		key = `${this._instanceId}-${key}`;
		this._registeredDecorationTypes[key] = true;
		this._codeEditorService.registerDecorationType(`exthost-api-${extensionId}`, key, options);
	}