Dynamic updating recent menu for tabs from other devices.

chrome/browser/ui/toolbar/recent_tabs_sub_menu_model.cc

Index: chrome/browser/ui/toolbar/recent_tabs_sub_menu_model.cc
diff --git a/chrome/browser/ui/toolbar/recent_tabs_sub_menu_model.cc b/chrome/browser/ui/toolbar/recent_tabs_sub_menu_model.cc
index 1cd8dbb53938649b46e6fe1d8814cff42fc41596..507f56855f2cf807c33a56c3e92d1f0cda42bf52 100644
--- a/chrome/browser/ui/toolbar/recent_tabs_sub_menu_model.cc
+++ b/chrome/browser/ui/toolbar/recent_tabs_sub_menu_model.cc
@@ -179,11 +179,9 @@ const int RecentTabsSubMenuModel::kDisabledRecentlyClosedHeaderCommandId = 1121;
 
 RecentTabsSubMenuModel::RecentTabsSubMenuModel(
     ui::AcceleratorProvider* accelerator_provider,
-    Browser* browser,
-    sync_sessions::OpenTabsUIDelegate* open_tabs_delegate)
+    Browser* browser)
     : ui::SimpleMenuModel(this),
       browser_(browser),
-      open_tabs_delegate_(open_tabs_delegate),
       last_local_model_index_(kHistorySeparatorIndex),
       default_favicon_(
           ui::ResourceBundle::GetSharedInstance().GetNativeImageNamed(
@@ -204,6 +202,15 @@ RecentTabsSubMenuModel::RecentTabsSubMenuModel(
 #endif
   }
 
+#if !defined(OS_MACOSX)

[Peter Kasting, 2017/03/23 04:48:34]

Nit: Add note about why this isn't on for Mac

+  browser_sync::ProfileSyncService* sync_service =
+      ProfileSyncServiceFactory::GetInstance()->GetForProfile(
+          browser_->profile());
+  if (sync_service && sync_service->IsSyncActive()) {

[Peter Kasting, 2017/03/23 04:48:34]

Nit: No {}

+    sync_service->AddObserver(this);
+  }
+#endif
+
   Build();
 
   // Retrieve accelerator key for IDC_RESTORE_TAB now, because on ASH, it's not
@@ -236,6 +243,15 @@ RecentTabsSubMenuModel::~RecentTabsSubMenuModel() {
       TabRestoreServiceFactory::GetForProfile(browser_->profile());
   if (service)
     service->RemoveObserver(this);
+
+#if !defined(OS_MACOSX)
+  browser_sync::ProfileSyncService* sync_service =
+      ProfileSyncServiceFactory::GetInstance()->GetForProfile(
+          browser_->profile());
+  if (sync_service) {
+    sync_service->RemoveObserver(this);

[Peter Kasting, 2017/03/23 04:48:34]

Can this be done with a ScopedObserver class member instead of manual Add/Remove
calls?  Or is it possible that the sync service will be torn down while the menu
is open?  (I would think a ScopedObserver would work, and for the
TabRestoreService as well.)

+  }
+#endif
 }
 
 bool RecentTabsSubMenuModel::IsCommandIdChecked(int command_id) const {
@@ -474,8 +490,7 @@ void RecentTabsSubMenuModel::BuildLocalEntries() {
 
 void RecentTabsSubMenuModel::BuildTabsFromOtherDevices() {
   // All other devices' items (device headers or tabs) use AddItem*() to append
-  // a menu item, because they are always only built once (i.e. invoked from
-  // Constructor()) and don't change after that.
+  // a menu item, because they take always place in the end of menu.
 
   sync_sessions::OpenTabsUIDelegate* open_tabs = GetOpenTabsUIDelegate();
   std::vector<const sync_sessions::SyncedSession*> sessions;
@@ -708,6 +723,20 @@ void RecentTabsSubMenuModel::ClearLocalEntries() {
   local_window_items_.clear();
 }
 
+void RecentTabsSubMenuModel::ClearTabsFromOtherDevices() {
+  DCHECK_GE(last_local_model_index_, 0);
+  int count = GetItemCount();
+  for (int index = count - 1; index > last_local_model_index_; --index)
+    RemoveItemAt(index);
+
+  // Cancel asynchronous FaviconService::GetFaviconImageForPageURL() tasks of

[Peter Kasting, 2017/03/23 04:48:34]

Nit: These comments (here and below) add nothing to the code, remove them.

+  // all tabs from the other devices.
+  other_devices_tab_cancelable_task_tracker_.TryCancelAll();
+
+  // Remove all tab from the other devices navigation items.
+  other_devices_tab_navigation_items_.clear();
+}
+
 sync_sessions::OpenTabsUIDelegate*
 RecentTabsSubMenuModel::GetOpenTabsUIDelegate() {
   if (!open_tabs_delegate_) {
@@ -736,3 +765,14 @@ void RecentTabsSubMenuModel::TabRestoreServiceDestroyed(
     sessions::TabRestoreService* service) {
   TabRestoreServiceChanged(service);
 }
+
+void RecentTabsSubMenuModel::OnForeignSessionUpdated(
+    syncer::SyncService* sync) {
+  ClearTabsFromOtherDevices();
+
+  BuildTabsFromOtherDevices();
+
+  ui::MenuModelDelegate* menu_model_delegate = GetMenuModelDelegate();
+  if (menu_model_delegate)
+    menu_model_delegate->OnMenuStructureChanged();
+}