Bug 1689684 - Ensure docshell/test/browser/browser_bug1347823.js works with SHIP-BFCache, r=peterv

Depends on D109312

Differential Revision: https://phabricator.services.mozilla.com/D109313

docshell/test/browser/browser.ini

@@ -93,7 +93,6 @@ skip-if =
 [browser_bug1309900_crossProcessHistoryNavigation.js]
 [browser_bug1328501.js]
 [browser_bug1347823.js]
-fail-if = sessionHistoryInParent
 [browser_bug134911.js]
 [browser_bug1415918_beforeunload_options.js]
 [browser_bug1622420.js]

docshell/test/browser/browser_bug1347823.js

@@ -7,7 +7,11 @@
 add_task(async function testValidCache() {
   // Make an unrealistic large timeout.
   await SpecialPowers.pushPrefEnv({
-    set: [["browser.sessionhistory.contentViewerTimeout", 86400]],
+    set: [
+      ["browser.sessionhistory.contentViewerTimeout", 86400],
+      // If Fission is disabled, the pref is no-op.
+      ["fission.bfcacheInParent", true],
+    ],
   });
 
   await BrowserTestUtils.withNewTab(
@@ -40,7 +44,11 @@ add_task(async function testValidCache() {
 add_task(async function testExpiredCache() {
   // Make bfcache timeout in 1 sec.
   await SpecialPowers.pushPrefEnv({
-    set: [["browser.sessionhistory.contentViewerTimeout", 1]],
+    set: [
+      ["browser.sessionhistory.contentViewerTimeout", 1],
+      // If Fission is disabled, the pref is no-op.
+      ["fission.bfcacheInParent", true],
+    ],
   });
 
   await BrowserTestUtils.withNewTab(