src/vs/workbench/browser/parts/editor/textEditor.ts/AbstractTextEditor/getActiveResource
class AbstractTextEditor:	private getActiveResource(): URI | undefined {
		const mainControl = this.getMainControl();
		if (mainControl) {
			const model = mainControl.getModel();
			if (model) {
				return model.uri;
			}
		}

		if (this.input) {
			return this.input.resource;
		}

		return undefined;
	}