Auto rewrite vscode-resource entries in csp in web iframe based webviews

src/vs/workbench/contrib/webview/browser/pre/main.js

@@ -289,6 +289,11 @@
 			const csp = newDocument.querySelector('meta[http-equiv="Content-Security-Policy"]');
 			if (!csp) {
 				host.postMessage('no-csp-found');
+			} else {
+				// Rewrite vscode-resource in csp
+				if (data.endpoint) {
+					csp.setAttribute('content', csp.getAttribute('content').replace(/vscode-resource:/g, data.endpoint));
+				}
 			}
 
 			// set DOCTYPE for newDocument explicitly as DOMParser.parseFromString strips it off

src/vs/workbench/contrib/webview/browser/webviewElement.ts

@@ -202,7 +202,8 @@ export class IFrameWebview extends Disposable implements Webview {
 		this._send('content', {
 			contents: this.content.html,
 			options: this.content.options,
-			state: this.content.state
+			state: this.content.state,
+			endpoint: this.endpoint,
 		});
 	}