Move over csp and loading to use webpack

extensions/markdown/preview-src/loading.ts

@@ -0,0 +1,36 @@
+/*---------------------------------------------------------------------------------------------
+ *  Copyright (c) Microsoft Corporation. All rights reserved.
+ *  Licensed under the MIT License. See License.txt in the project root for license information.
+ *--------------------------------------------------------------------------------------------*/
+(function () {
+	const unloadedStyles: string[] = [];
+
+	const settings: any = JSON.parse(document.getElementById('vscode-markdown-preview-data').getAttribute('data-settings'));
+
+	const onStyleLoadError = (event: any) => {
+		const source = event.target.dataset.source;
+		unloadedStyles.push(source);
+	};
+
+	window.addEventListener('DOMContentLoaded', () => {
+		for (const link of document.getElementsByClassName('code-user-style') as HTMLCollectionOf<HTMLElement>) {
+			if (link.dataset.source) {
+				link.onerror = onStyleLoadError;
+			}
+		}
+	});
+
+	window.addEventListener('load', () => {
+		if (!unloadedStyles.length) {
+			return;
+		}
+		window.parent.postMessage({
+			type: 'command',
+			source: settings.source,
+			body: {
+				command: '_markdown.onPreviewStyleLoadError',
+				args: [unloadedStyles]
+			}
+		}, '*');
+	});
+})();