Ensure History > Recent Tabs restore preserves window disposition.

chrome/browser/ui/toolbar/recent_tabs_sub_menu_model.cc

 // Copyright 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "chrome/browser/ui/toolbar/recent_tabs_sub_menu_model.h"
 
 #include <stddef.h>
 
 #include "base/bind.h"
 #include "base/metrics/histogram_macros.h"
@@ skipping 446 matching lines @@
           auto& tab =
               static_cast<const sessions::TabRestoreService::Tab&>(*entry);
           const sessions::SerializedNavigationEntry& current_navigation =
               tab.navigations.at(tab.current_navigation_index);
           BuildLocalTabItem(entry->id, current_navigation.title(),
                             current_navigation.virtual_url(),
                             ++last_local_model_index_);
           break;
         }
         case sessions::TabRestoreService::WINDOW: {
-          BuildLocalWindowItem(
-              entry->id,
-              static_cast<const sessions::TabRestoreService::Window&>(*entry)
-                  .tabs.size(),
-              ++last_local_model_index_);
+          auto& window =
+              static_cast<const sessions::TabRestoreService::Window&>(*entry);
+          // Generate a window entry if the window contained more than 1 tab.
+          if (window.tabs.size() > 1) {

[sky, 2017/05/08 22:51:36]

We shouldn't need the special case here. Whether you get a tab vs a window
should depend upon how you closed the window. If you close the window, then you
should get a window entry, if you close the last tab in a window then I would
expect a tab entry.

[chrisha, 2017/05/09 15:44:54]

Moved this discussion to the bug, as it's slightly broader scope that in this
code review.

+            BuildLocalWindowItem(entry->id, window.tabs.size(),
+                                 ++last_local_model_index_);
+          } else {
+            // Otherwise, generate a tab entry. This fixes
+            // http://crbug.com/56744.
+            auto& tab = *window.tabs[0];
+            const sessions::SerializedNavigationEntry& current_navigation =
+                tab.navigations.at(tab.current_navigation_index);
+            BuildLocalTabItem(entry->id, current_navigation.title(),
+                              current_navigation.virtual_url(),
+                              ++last_local_model_index_);
+          }
           break;
         }
       }
       ++added_count;
     }
   }
   DCHECK_GE(last_local_model_index_, 0);
 }
 
 void RecentTabsSubMenuModel::BuildTabsFromOtherDevices() {
@@ skipping 279 matching lines @@
 void RecentTabsSubMenuModel::OnForeignSessionUpdated(
     syncer::SyncService* sync) {
   ClearTabsFromOtherDevices();
 
   BuildTabsFromOtherDevices();
 
   ui::MenuModelDelegate* menu_model_delegate = GetMenuModelDelegate();
   if (menu_model_delegate)
     menu_model_delegate->OnMenuStructureChanged();
 }