Bug 1668586 - stop messing with web progress listeners when changing remoteness, r=mattwoodrow

Differential Revision: https://phabricator.services.mozilla.com/D92514

Author: gijsk

toolkit/content/tests/browser/browser.ini

@@ -118,6 +118,7 @@ skip-if = os == "linux" && bits == 64 && os_version = "18.04" # Bug 1614739
 [browser_isSynthetic.js]
 [browser_keyevents_during_autoscrolling.js]
 [browser_label_textlink.js]
+[browser_remoteness_change_listeners.js]
 [browser_suspend_videos_outside_viewport.js]
 support-files =
   file_outside_viewport_videos.html

toolkit/content/tests/browser/browser_remoteness_change_listeners.js

@@ -0,0 +1,39 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+"use strict";
+
+/**
+ * Check that adding progress listeners to a browser doesn't break things
+ * when switching the remoteness of that browser.
+ */
+add_task(async function test_remoteness_switch_listeners() {
+  await BrowserTestUtils.withNewTab("about:support", async function(browser) {
+    let wpl;
+    let navigated = new Promise(resolve => {
+      wpl = {
+        onLocationChange() {
+          is(browser.currentURI.spec, "https://example.com/");
+          if (browser.currentURI?.spec == "https://example.com/") {
+            resolve();
+          }
+        },
+        QueryInterface: ChromeUtils.generateQI([
+          Ci.nsISupportsWeakReference,
+          Ci.nsIWebProgressListener2,
+          Ci.nsIWebProgressListener,
+        ]),
+      };
+      browser.addProgressListener(wpl);
+    });
+
+    let loaded = BrowserTestUtils.browserLoaded(
+      browser,
+      null,
+      "https://example.com/"
+    );
+    BrowserTestUtils.loadURI(browser, "https://example.com/");
+    await Promise.all([loaded, navigated]);
+    browser.removeProgressListener(wpl);
+  });
+});

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

@@ -920,22 +920,6 @@
       );
     }
 
-    /**
-     * Move the previously-tracked web progress listeners to this <browser>'s
-     * current WebProgress.
-     */
-    restoreProgressListeners() {
-      let listeners = this.progressListeners;
-      this.progressListeners = [];
-
-      for (let { weakListener, mask } of listeners) {
-        let listener = weakListener.get();
-        if (listener) {
-          this.addProgressListener(listener, mask);
-        }
-      }
-    }
-
     onPageHide(aEvent) {
       if (!this.docShell || !this.fastFind) {
         return;
@@ -1050,7 +1034,6 @@
          * the <browser> element may not be initialized yet.
          */
 
-        let oldNavigation = this._remoteWebNavigation;
         this._remoteWebNavigation = new LazyModules.RemoteWebNavigation(this);
 
         // Initialize contentPrincipal to the about:blank principal for this loadcontext
@@ -1064,13 +1047,6 @@
         // we should re-evaluate the CSP here.
         this._csp = null;
 
-        if (!oldNavigation) {
-          // If we weren't remote, then we're transitioning from local to
-          // remote. Add all listeners from the previous <browser> to the new
-          // RemoteWebProgress.
-          this.restoreProgressListeners();
-        }
-
         this.messageManager.loadFrameScript(
           "chrome://global/content/browser-child.js",
           true
@@ -1119,7 +1095,6 @@
 
       if (!this.isRemoteBrowser) {
         this._remoteWebNavigation = null;
-        this.restoreProgressListeners();
         this.addEventListener("pagehide", this.onPageHide, true);
       }
     }