Backed out changeset 51ffa59f1488 (bug 1521923) for WR failures on outline-013.html . CLOSED TREE

browser/base/content/browser.js

@@ -1408,9 +1408,6 @@ var gBrowserInit = {
     // avoid an about:blank flash.
     let tabToAdopt = this.getTabToAdopt();
     if (tabToAdopt) {
-      let evt = new CustomEvent("before-initial-tab-adopted", { bubbles: true });
-      gBrowser.tabpanels.dispatchEvent(evt);
-
       // Stop the about:blank load
       gBrowser.stop();
       // make sure it has a docshell

browser/base/content/tabbrowser.js

@@ -3703,6 +3703,13 @@ window._gBrowser = {
       return this.replaceTabWithWindow(tabs[0], aOptions);
     }
 
+    // The order of the tabs is preserved.
+    // To avoid multiple tab-switch, the active tab is "moved" last, if applicable.
+    // If applicable, the active tab remains active in the new window.
+    let activeTab = gBrowser.selectedTab;
+    let inactiveTabs = tabs.filter(t => t != activeTab);
+    let activeTabNewIndex = tabs.indexOf(activeTab);
+
     // Play the closing animation for all selected tabs to give
     // immediate feedback while waiting for the new window to appear.
     if (this.animationsEnabled) {
@@ -3712,28 +3719,33 @@ window._gBrowser = {
       }
     }
 
-    // Create a new window and make it adopt the tabs, preserving their relative order.
+    let win;
-    // The initial tab of the new window will be selected, so it should adopt the
+    let firstInactiveTab = inactiveTabs[0];
-    // selected tab of the original window, if applicable, or else the first moving tab.
+
-    // This avoids tab-switches in the new window, preserving tab laziness.
+    let adoptRemainingTabs = () => {
-    // However, to avoid multiple tab-switches in the original window, the other tabs
+      for (let i = 1; i < inactiveTabs.length; i++) {
-    // should be adopted before the selected one.
+        win.gBrowser.adoptTab(inactiveTabs[i], i);
-    let selectedTabIndex = Math.max(0, tabs.indexOf(gBrowser.selectedTab));
-    let selectedTab = tabs[selectedTabIndex];
-    let win = this.replaceTabWithWindow(selectedTab, aOptions);
-    win.addEventListener("before-initial-tab-adopted", () => {
-      for (let i = 0; i < tabs.length; ++i) {
-        if (i != selectedTabIndex) {
-          win.gBrowser.adoptTab(tabs[i], i);
       }
+
+      if (activeTabNewIndex > -1) {
+        win.gBrowser.adoptTab(activeTab, activeTabNewIndex, true /* aSelectTab */);
       }
+
       // Restore tab selection
       let winVisibleTabs = win.gBrowser.visibleTabs;
       let winTabLength = winVisibleTabs.length;
       win.gBrowser.addRangeToMultiSelectedTabs(winVisibleTabs[0],
                                                winVisibleTabs[winTabLength - 1]);
-      win.gBrowser.lockClearMultiSelectionOnce();
+    };
-    }, {once: true});
+
+    // Pending tabs don't get their docshell swapped, wait for their TabClose
+    if (firstInactiveTab.hasAttribute("pending")) {
+      firstInactiveTab.addEventListener("TabClose", adoptRemainingTabs, {once: true});
+    } else {
+      firstInactiveTab.linkedBrowser.addEventListener("EndSwapDocShells", adoptRemainingTabs, {once: true});
+    }
+
+    win = this.replaceTabWithWindow(firstInactiveTab, aOptions);
     return win;
   },
 

browser/base/content/test/tabs/browser_multiselect_tabs_move_to_new_window_contextmenu.js

@@ -95,20 +95,20 @@ add_task(async function testLazyTabs() {
   let newTabs = newWindow.gBrowser.tabs;
 
   isnot(newTabs[0].linkedPanel, "", `New tab 0 should continue not being lazy`);
-  for (let i = 1; i < numTabs; ++i) {
+  // FIXME: bug 1521923 - First inactive tab to be moved into another window loses laziness
+  todo_is(newTabs[1].linkedPanel, "", `New tab 1 should continue being lazy`);
+  for (let i = 2; i < numTabs; ++i) {
     is(newTabs[i].linkedPanel, "", `New tab ${i} should continue being lazy`);
   }
 
   is(newTabs[0].linkedBrowser.currentURI.spec, `http://example.com/?0`,
     `New tab 0 should have the right URL`);
-  for (let i = 1; i < numTabs; ++i) {
+  todo_is(SessionStore.getLazyTabValue(newTabs[1], "url"), `http://example.com/?1`,
+    `New tab 1 should have the right lazy URL`);
+  for (let i = 2; i < numTabs; ++i) {
     is(SessionStore.getLazyTabValue(newTabs[i], "url"), `http://example.com/?${i}`,
       `New tab ${i} should have the right lazy URL`);
   }
 
-  for (let i = 0; i < numTabs; ++i) {
-    ok(newTabs[i].multiselected, `New tab ${i} should be multiselected`);
-  }
-
   BrowserTestUtils.closeWindow(newWindow);
 });