Bug 1728332 - Part 1: Predict remote type when inserting restored tabs, r=Gijs

This should mostly avoid the issue where newly created pinned tabs when
restoring a session are first created in the shared web process, and
migrated into the correct process upon navigating. I also added
remoteType prediction to the undoCloseTab and duplicateTab codepaths
to avoid unnecessary process changes there as well.

Differential Revision: https://phabricator.services.mozilla.com/D141146

browser/base/content/tabbrowser.js

@@ -2987,9 +2987,7 @@
             restoreTabsLazily && !select && !tabData.pinned;
 
           let url = "about:blank";
-          if (createLazyBrowser && tabData.entries && tabData.entries.length) {
-            // Let tabbrowser know the future URI because progress listeners won't
-            // get onLocationChange notification before the browser is inserted.
+          if (tabData.entries?.length) {
             let activeIndex = (tabData.index || tabData.entries.length) - 1;
             // Ensure the index is in bounds.
             activeIndex = Math.min(activeIndex, tabData.entries.length - 1);
@@ -2997,10 +2995,23 @@
             url = tabData.entries[activeIndex].url;
           }
 
+          let preferredRemoteType = E10SUtils.getRemoteTypeForURI(
+            url,
+            gMultiProcessBrowser,
+            gFissionBrowser,
+            E10SUtils.DEFAULT_REMOTE_TYPE,
+            null,
+            E10SUtils.predictOriginAttributes({ window, userContextId })
+          );
+
+          // If we're creating a lazy browser, let tabbrowser know the future
+          // URI because progress listeners won't get onLocationChange
+          // notification before the browser is inserted.
+          //
           // Setting noInitialLabel is a perf optimization. Rendering tab labels
           // would make resizing the tabs more expensive as we're adding them.
           // Each tab will get its initial label set in restoreTab.
-          tab = this.addTrustedTab(url, {
+          tab = this.addTrustedTab(createLazyBrowser ? url : "about:blank", {
             createLazyBrowser,
             skipAnimation: true,
             allowInheritPrincipal: true,
@@ -3009,6 +3020,8 @@
             skipBackgroundNotify: true,
             bulkOrderedOpen: true,
             batchInsertingTabs: true,
+            skipLoad: !createLazyBrowser,
+            preferredRemoteType,
           });
 
           if (select) {

browser/components/sessionstore/SessionStore.jsm

@@ -3110,6 +3110,7 @@ var SessionStoreInternal = {
         ? { relatedToCurrent: true, ownerTab: aTab }
         : {}),
       skipLoad: true,
+      preferredRemoteType: aTab.linkedBrowser.remoteType,
     };
     let newTab = aWindow.gBrowser.addTrustedTab(null, tabOptions);
 
@@ -3246,12 +3247,35 @@ var SessionStoreInternal = {
       aIndex
     );
 
+    // Predict the remote type to use for the load to avoid unnecessary process
+    // switches.
+    let preferredRemoteType = E10SUtils.DEFAULT_REMOTE_TYPE;
+    if (state.entries?.length) {
+      let activeIndex = (state.index || state.entries.length) - 1;
+      activeIndex = Math.min(activeIndex, state.entries.length - 1);
+      activeIndex = Math.max(activeIndex, 0);
+
+      preferredRemoteType = E10SUtils.getRemoteTypeForURI(
+        state.entries[activeIndex].url,
+        aWindow.gMultiProcessBrowser,
+        aWindow.gFissionBrowser,
+        E10SUtils.DEFAULT_REMOTE_TYPE,
+        null,
+        E10SUtils.predictOriginAttributes({
+          window: aWindow,
+          userContextId: state.userContextId,
+        })
+      );
+    }
+
     // create a new tab
     let tabbrowser = aWindow.gBrowser;
     let tab = (tabbrowser.selectedTab = tabbrowser.addTrustedTab(null, {
       index: pos,
       pinned: state.pinned,
       userContextId: state.userContextId,
+      skipLoad: true,
+      preferredRemoteType,
     }));
 
     // restore tab content

browser/components/sessionstore/test/browser_restore_container_tabs_oa.js

@@ -201,31 +201,10 @@ add_task(async function testRestore() {
       let uri = container_tab.linkedBrowser.currentURI.spec;
 
       // Verify XULFrameLoaderCreated was fired once
-      if (
-        test_page_data.uri == "about:preferences" ||
-        test_page_data.uri == "about:config" ||
-        gFissionBrowser
-      ) {
-        todo_is(
-          xulFrameLoaderCreatedCounter.numCalledSoFar,
-          1,
-          `XULFrameLoaderCreated was fired once, when restoring ${uri} in container ${userContextId} `
-        );
-      } else {
-        is(
-          xulFrameLoaderCreatedCounter.numCalledSoFar,
-          1,
-          `XULFrameLoaderCreated was fired once, when restoring ${uri} in container ${userContextId} `
-        );
-      }
-      // While the above assertion is `todo_is`, ensure that we don't have a regression
-      // from current behaviour by checking that the event is fired < 3 times.
-      info(
-        `XULFrameLoaderCreated has been fired ${xulFrameLoaderCreatedCounter.numCalledSoFar} times, when restoring ${uri} in container ${userContextId}`
-      );
-      ok(
-        xulFrameLoaderCreatedCounter.numCalledSoFar <= 2,
-        `XULFrameLoaderCreated was fired [1,2] times, when restoring ${uri} in container ${userContextId} `
+      is(
+        xulFrameLoaderCreatedCounter.numCalledSoFar,
+        1,
+        `XULFrameLoaderCreated was fired once, when restoring ${uri} in container ${userContextId} `
       );
       container_tab.ownerGlobal.gBrowser.removeEventListener(
         "XULFrameLoaderCreated",