Scaffold: Improve cookie handling

- Use cookies from browser pane when running detectWeb or doWeb
- Use cookies from document when running or updating tests

This should fix various cases where translators can't be properly
developed or tested in Scaffold (e.g., [1]).

[1] https://github.com/zotero/translators/pull/2296#issuecomment-739116620

chrome/content/scaffold/scaffold.js

@@ -514,6 +514,13 @@ var Scaffold = new function() {
 				return;
 			}
 			translate.setDocument(input);
+			
+			// Use cookies from browser pane
+			translate.setCookieSandbox(new Zotero.CookieSandbox(
+				null,
+				_getDocumentURL(input),
+				input.cookie
+			));
 		} else if (functionToRun == "detectImport" || functionToRun == "doImport") {
 			var translate = new Zotero.Translate.Import();
 			translate.setString(input);

chrome/content/zotero/tools/testTranslators/translatorTester.js

@@ -425,6 +425,9 @@ Zotero_TranslatorTester.prototype.fetchPageAndRunTest = function (test, testDone
 						+ " second(s) for page content to settle");
 				}
 				setTimeout(() => {
+					// Use cookies from document in translator HTTP requests
+					this._cookieSandbox = new Zotero.CookieSandbox(null, test.url, doc.cookie);
+					
 					this.runTest(test, doc, function (obj, test, status, message) {
 						Zotero.Browser.deleteHiddenBrowser(browser);
 						testDoneCallback(obj, test, status, message);
@@ -639,6 +642,14 @@ Zotero_TranslatorTester.prototype.newTest = function(doc, testReadyCallback) {
 		translate.setTranslatorProvider(this.translatorProvider);
 	}
 	translate.setDocument(doc);
+	// Use cookies from document
+	if (doc.cookie) {
+		translate.setCookieSandbox(new Zotero.CookieSandbox(
+			null,
+			doc.location.href,
+			doc.cookie
+		));
+	}
 	translate.setTranslator(this.translator);
 	translate.setHandler("debug", this._debug);
 	translate.setHandler("select", function(obj, items, callback) {