Bug 1657992 - Handle middle-click on long-press backForwardMenu only once + tests r=dao

Differential Revision: https://phabricator.services.mozilla.com/D86784

browser/base/content/browser.xhtml

@@ -208,7 +208,9 @@
     </menupopup>
 
     <!-- bug 415444/582485: event.stopPropagation is here for the cloned version
-         of this menupopup -->
+         of this menupopup, to prevent already-handled clicks on menu items from
+         propagating to the back or forward button.
+    -->
     <menupopup id="backForwardMenu"
                onpopupshowing="return FillHistoryMenu(event.target);"
                oncommand="gotoHistoryIndex(event); event.stopPropagation();"

browser/base/content/test/backforward/.eslintrc.js

@@ -0,0 +1,5 @@
+"use strict";
+
+module.exports = {
+  extends: ["plugin:mozilla/browser-test"],
+};

browser/base/content/test/backforward/browser.ini

@@ -0,0 +1 @@
+[browser_longpress_session_history_menu.js]

browser/base/content/test/backforward/browser_longpress_session_history_menu.js

@@ -0,0 +1,70 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+// Tests that the session history can be shown by long-pressing the back button.
+// And that middle-click opens one tab (as a regression test for bug 1657992).
+add_task(async function restore_history_entry_by_middle_click() {
+  let tab1 = await BrowserTestUtils.openNewForegroundTab(
+    gBrowser,
+    "http://example.com"
+  );
+
+  await SpecialPowers.spawn(tab1.linkedBrowser, [], () => {
+    content.history.pushState(null, null, "2.html");
+    content.history.pushState(null, null, "3.html");
+  });
+
+  await new Promise(resolve => SessionStore.getSessionHistory(tab1, resolve));
+
+  let backButton = document.getElementById("back-button");
+  // This is the popup (clone of backForwardMenu) from SetClickAndHoldHandlers.
+  let historyMenu = backButton.firstElementChild;
+
+  info("waiting for the history menu to open");
+
+  let popupShownPromise = BrowserTestUtils.waitForEvent(
+    historyMenu,
+    "popupshown"
+  );
+
+  // Trigger gClickAndHoldListenersOnElement logic in browser.js to open the
+  // history menu that opens after a long press.
+  EventUtils.synthesizeMouseAtCenter(backButton, { type: "mousedown" });
+  let event = await popupShownPromise;
+  EventUtils.synthesizeMouseAtCenter(backButton, { type: "mouseup" });
+
+  info("Waiting for menu items to be populated");
+  await new Promise(resolve => SessionStore.getSessionHistory(tab1, resolve));
+
+  SimpleTest.isDeeply(
+    Array.from(event.target.children, node => node.getAttribute("uri")),
+    [
+      "http://example.com/3.html",
+      "http://example.com/2.html",
+      "http://example.com/",
+    ],
+    "Expected session history items"
+  );
+  let historyMenuItem = event.target.children[1];
+
+  let popupHiddenPromise = BrowserTestUtils.waitForEvent(
+    historyMenu,
+    "popuphidden"
+  );
+
+  let tabRestoredPromise = BrowserTestUtils.waitForEvent(
+    gBrowser.tabContainer,
+    "SSTabRestored"
+  );
+
+  EventUtils.sendMouseEvent({ type: "click", button: 1 }, historyMenuItem);
+
+  info("Waiting for history menu to be hidden");
+  await popupHiddenPromise;
+  info("Waiting for history item to be restored in a new tab");
+  let newTab = (await tabRestoredPromise).target;
+  is(newTab.linkedBrowser.currentURI.spec, "http://example.com/2.html");
+
+  BrowserTestUtils.removeTab(newTab);
+  BrowserTestUtils.removeTab(tab1);
+});

browser/base/content/utilityOverlay.js

@@ -732,6 +732,11 @@ function checkForMiddleClick(node, event) {
     );
     node.dispatchEvent(cmdEvent);
 
+    // Stop the propagation of the click event, to prevent the event from being
+    // handled more than once.
+    // E.g. see https://bugzilla.mozilla.org/show_bug.cgi?id=1657992#c4
+    event.stopPropagation();
+
     // If the middle-click was on part of a menu, close the menu.
     // (Menus close automatically with left-click but not with middle-click.)
     closeMenus(event.target);

browser/base/moz.build

@@ -20,6 +20,7 @@ MOCHITEST_CHROME_MANIFESTS += [
 BROWSER_CHROME_MANIFESTS += [
     'content/test/about/browser.ini',
     'content/test/alerts/browser.ini',
+    'content/test/backforward/browser.ini',
     'content/test/caps/browser.ini',
     'content/test/captivePortal/browser.ini',
     'content/test/contextMenu/browser.ini',