Bug 1656997 - When session history runs in the parent process, SessionStore should not modify the session history when doing process switches, r=nika,mconley

Differential Revision: https://phabricator.services.mozilla.com/D86073

browser/base/content/tabbrowser.js

@@ -29,6 +29,12 @@
         "UrlbarProviderOpenTabs",
         "resource:///modules/UrlbarProviderOpenTabs.jsm"
       );
+      XPCOMUtils.defineLazyPreferenceGetter(
+        this,
+        "sessionHistoryInParent",
+        "fission.sessionHistoryInParent",
+        false
+      );
 
       Services.obs.addObserver(this, "contextual-identity-updated");
 
@@ -1979,8 +1985,10 @@
 
       // Ensure that SessionStore has flushed any session history state from the
       // content process before we this browser's remoteness.
-      b.prepareToChangeRemoteness = () =>
+      if (!this.sessionHistoryInParent) {
-        SessionStore.prepareToChangeRemoteness(b);
+        b.prepareToChangeRemoteness = () =>
+          SessionStore.prepareToChangeRemoteness(b);
+      }
 
       const defaultBrowserAttributes = {
         contextmenu: "contentAreaContextMenu",

toolkit/content/widgets/browser-custom-element.js

@@ -18,6 +18,10 @@
     "resource://gre/modules/BrowserUtils.jsm"
   );
 
+  const { XPCOMUtils } = ChromeUtils.import(
+    "resource://gre/modules/XPCOMUtils.jsm"
+  );
+
   let LazyModules = {};
 
   ChromeUtils.defineModuleGetter(
@@ -44,10 +48,12 @@
     "resource://gre/actors/PopupBlockingParent.jsm"
   );
 
-  ChromeUtils.defineModuleGetter(
+  let lazyPrefs = {};
-    LazyModules,
+  XPCOMUtils.defineLazyPreferenceGetter(
-    "XPCOMUtils",
+    lazyPrefs,
-    "resource://gre/modules/XPCOMUtils.jsm"
+    "sessionHistoryInParent",
+    "fission.sessionHistoryInParent",
+    false
   );
 
   const elementsToDestroyOnUnload = new Set();
@@ -90,7 +96,7 @@
       // between calls to destroy().
       this.progressListeners = [];
 
-      LazyModules.XPCOMUtils.defineLazyGetter(this, "popupBlocker", () => {
+      XPCOMUtils.defineLazyGetter(this, "popupBlocker", () => {
         return new LazyModules.PopupBlocker(this);
       });
 
@@ -1872,10 +1878,12 @@
       // history, and performing the `resumeRedirectedLoad`, in order to get
       // sesssion state set up correctly.
       // FIXME: This probably needs to be hookable by GeckoView.
-      let tabbrowser = this.getTabBrowser();
+      if (!lazyPrefs.sessionHistoryInParent) {
-      if (tabbrowser) {
+        let tabbrowser = this.getTabBrowser();
-        tabbrowser.finishBrowserRemotenessChange(this, redirectLoadSwitchId);
+        if (tabbrowser) {
-        return true;
+          tabbrowser.finishBrowserRemotenessChange(this, redirectLoadSwitchId);
+          return true;
+        }
       }
       return false;
     }