[JS] UserActivation must be enabled before running document actions

else auto-print is broken (it's a regression from patch #15822).

src/scripting_api/event.js

@@ -91,6 +91,9 @@ class EventDispatcher {
       if (id === "doc") {
         const eventName = event.name;
         if (eventName === "Open") {
+          // The user has decided to open this pdf, hence we enable
+          // userActivation.
+          this.userActivation();
           // Initialize named actions before calling formatAll to avoid any
           // errors in the case where a formatter is using one of those named
           // actions (see #15818).

test/integration/scripting_spec.js

@@ -1753,4 +1753,31 @@ describe("Interaction", () => {
       );
     });
   });
+
+  describe("in autoprint.pdf", () => {
+    let pages;
+
+    beforeAll(async () => {
+      pages = await loadAndWait("autoprint.pdf", ".endOfContent");
+    });
+
+    afterAll(async () => {
+      await closePages(pages);
+    });
+
+    it("must check if printing is triggered when the document is open", async () => {
+      await Promise.all(
+        pages.map(async ([browserName, page]) => {
+          await page.waitForFunction(
+            "window.PDFViewerApplication.scriptingReady === true"
+          );
+
+          await page.waitForFunction(
+            `document.querySelector(".printedPage") !== null`
+          );
+          await page.keyboard.press("Escape");
+        })
+      );
+    });
+  });
 });

test/pdfs/.gitignore

@@ -563,3 +563,4 @@
 !fields_order.pdf
 !issue15815.pdf
 !issue15818.pdf
+!autoprint.pdf