[ios] Move PerformBatchOperation() out of WebStateList serialization

This CL moves PerformBatchOperations() out of the responsibility of
WebStateList serialization and into the caller's responsibility.

This allows callers to define what a batch operation is. For example,
when restoring closed tabs, a batch operation includes modifying
TabRestoreService at the same time as adding WebStates to the WebStateList.

Note: PerformBatchOperation was recently added to web_state_list_serialization
in this CL:
https://chromium-review.googlesource.com/c/chromium/src/+/1865161

Bug: 1014526
Change-Id: I40b11e4fe9b30a5fe18e0e8e404c298b04676d1e
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1867389
Commit-Queue: edchin <edchin@chromium.org>
Reviewed-by: edchin <edchin@chromium.org>
Reviewed-by: Sylvain Defresne <sdefresne@chromium.org>
Reviewed-by: Rohit Rao <rohitrao@chromium.org>
Cr-Commit-Position: refs/heads/master@{#707387}

ios/chrome/browser/tabs/tab_model.mm

@@ -574,11 +574,14 @@ void RecordMainFrameNavigationMetric(web::WebState* web_state) {
   int oldCount = _webStateList->count();
   DCHECK_GE(oldCount, 0);
 
-  web::WebState::CreateParams createParams(_browserState);
-  DeserializeWebStateList(
-      _webStateList, window,
-      base::BindRepeating(&web::WebState::CreateWithStorageSession,
-                          createParams));
+  _webStateList->PerformBatchOperation(
+      base::BindOnce(^(WebStateList* web_state_list) {
+        web::WebState::CreateParams createParams(_browserState);
+        DeserializeWebStateList(
+            web_state_list, window,
+            base::BindRepeating(&web::WebState::CreateWithStorageSession,
+                                createParams));
+      }));
 
   DCHECK_GT(_webStateList->count(), oldCount);
   int restoredCount = _webStateList->count() - oldCount;

ios/chrome/browser/ui/tab_grid/tab_grid_mediator.mm

@@ -330,26 +330,11 @@ web::WebState* GetWebStateWithId(WebStateList* web_state_list,
 - (void)undoCloseAllItems {
   if (!self.closedSessionWindow)
     return;
-  DCHECK(self.tabModel.browserState);
-  // Don't trigger the initial load for these restored WebStates since the
-  // number of WKWebViews is unbounded and may lead to an OOM crash.
-  WebStateListWebUsageEnabler* webUsageEnabler =
-      WebStateListWebUsageEnablerFactory::GetInstance()->GetForBrowserState(
-          self.tabModel.browserState);
-  webUsageEnabler->SetTriggersInitialLoad(false);
-  web::WebState::CreateParams createParams(self.tabModel.browserState);
-  DeserializeWebStateList(
-      self.webStateList, self.closedSessionWindow,
-      base::BindRepeating(&web::WebState::CreateWithStorageSession,
-                          createParams));
-  webUsageEnabler->SetTriggersInitialLoad(true);
-
-  self.closedSessionWindow = nil;
-  [self removeEntriesFromTabRestoreService];
-  self.closedTabsCount = 0;
-  // Unmark all images for deletion since they are now active tabs again.
-  ios::ChromeBrowserState* browserState = self.tabModel.browserState;
-  [SnapshotCacheFactory::GetForBrowserState(browserState) unmarkAllImages];
+  __weak TabGridMediator* weakSelf = self;
+  self.webStateList->PerformBatchOperation(
+      base::BindOnce(^(WebStateList* web_state_list) {
+        [weakSelf restoreClosedSessionWindowAndUpdateTabRestoreService];
+      }));
 }
 
 - (void)discardSavedClosedItems {
@@ -451,6 +436,33 @@ web::WebState* GetWebStateWithId(WebStateList* web_state_list,
   }
 }
 
+// Restores the saved |self.closedSessionWindow| and updates the
+// TabRestoreService.
+- (void)restoreClosedSessionWindowAndUpdateTabRestoreService {
+  if (!self.closedSessionWindow)
+    return;
+  DCHECK(self.tabModel.browserState);
+  // Don't trigger the initial load for these restored WebStates since the
+  // number of WKWebViews is unbounded and may lead to an OOM crash.
+  WebStateListWebUsageEnabler* webUsageEnabler =
+      WebStateListWebUsageEnablerFactory::GetInstance()->GetForBrowserState(
+          self.tabModel.browserState);
+  webUsageEnabler->SetTriggersInitialLoad(false);
+  web::WebState::CreateParams createParams(self.tabModel.browserState);
+  DeserializeWebStateList(
+      self.webStateList, self.closedSessionWindow,
+      base::BindRepeating(&web::WebState::CreateWithStorageSession,
+                          createParams));
+  webUsageEnabler->SetTriggersInitialLoad(true);
+
+  self.closedSessionWindow = nil;
+  [self removeEntriesFromTabRestoreService];
+  self.closedTabsCount = 0;
+  // Unmark all images for deletion since they are now active tabs again.
+  ios::ChromeBrowserState* browserState = self.tabModel.browserState;
+  [SnapshotCacheFactory::GetForBrowserState(browserState) unmarkAllImages];
+}
+
 // Returns a SnapshotCache for the current BrowserState.
 - (SnapshotCache*)snapshotCache {
   if (!_tabModel.browserState)

ios/chrome/browser/web_state_list/web_state_list_serialization.mm

@@ -27,12 +27,47 @@ namespace {
 // the WebStates stored in the WebStateList.
 NSString* const kOpenerIndexKey = @"OpenerIndex";
 NSString* const kOpenerNavigationIndexKey = @"OpenerNavigationIndex";
+}  // namespace
+
+SessionWindowIOS* SerializeWebStateList(WebStateList* web_state_list) {
+  NSMutableArray<CRWSessionStorage*>* serialized_session =
+      [NSMutableArray arrayWithCapacity:web_state_list->count()];
 
-// Helper for DeserializeWebStateList allowing the mutation to appears as a
-// single batched operation.
-void DeserializeWebStateListHelper(SessionWindowIOS* session_window,
-                                   const WebStateFactory& web_state_factory,
-                                   WebStateList* web_state_list) {
+  for (int index = 0; index < web_state_list->count(); ++index) {
+    web::WebState* web_state = web_state_list->GetWebStateAt(index);
+    WebStateOpener opener = web_state_list->GetOpenerOfWebStateAt(index);
+
+    web::SerializableUserDataManager* user_data_manager =
+        web::SerializableUserDataManager::FromWebState(web_state);
+
+    int opener_index = WebStateList::kInvalidIndex;
+    if (opener.opener) {
+      opener_index = web_state_list->GetIndexOfWebState(opener.opener);
+      DCHECK_NE(opener_index, WebStateList::kInvalidIndex);
+      user_data_manager->AddSerializableData(@(opener_index), kOpenerIndexKey);
+      user_data_manager->AddSerializableData(@(opener.navigation_index),
+                                             kOpenerNavigationIndexKey);
+    } else {
+      user_data_manager->AddSerializableData([NSNull null], kOpenerIndexKey);
+      user_data_manager->AddSerializableData([NSNull null],
+                                             kOpenerNavigationIndexKey);
+    }
+
+    [serialized_session addObject:web_state->BuildSessionStorage()];
+  }
+
+  NSUInteger selectedIndex =
+      web_state_list->active_index() != WebStateList::kInvalidIndex
+          ? static_cast<NSUInteger>(web_state_list->active_index())
+          : static_cast<NSUInteger>(NSNotFound);
+
+  return [[SessionWindowIOS alloc] initWithSessions:[serialized_session copy]
+                                      selectedIndex:selectedIndex];
+}
+
+void DeserializeWebStateList(WebStateList* web_state_list,
+                             SessionWindowIOS* session_window,
+                             const WebStateFactory& web_state_factory) {
   const int old_count = web_state_list->count();
   for (CRWSessionStorage* session in session_window.sessions) {
     std::unique_ptr<web::WebState> web_state = web_state_factory.Run(session);
@@ -75,48 +110,3 @@ void DeserializeWebStateListHelper(SessionWindowIOS* session_window,
         old_count + static_cast<int>(session_window.selectedIndex));
   }
 }
-}  // namespace
-
-SessionWindowIOS* SerializeWebStateList(WebStateList* web_state_list) {
-  NSMutableArray<CRWSessionStorage*>* serialized_session =
-      [NSMutableArray arrayWithCapacity:web_state_list->count()];
-
-  for (int index = 0; index < web_state_list->count(); ++index) {
-    web::WebState* web_state = web_state_list->GetWebStateAt(index);
-    WebStateOpener opener = web_state_list->GetOpenerOfWebStateAt(index);
-
-    web::SerializableUserDataManager* user_data_manager =
-        web::SerializableUserDataManager::FromWebState(web_state);
-
-    int opener_index = WebStateList::kInvalidIndex;
-    if (opener.opener) {
-      opener_index = web_state_list->GetIndexOfWebState(opener.opener);
-      DCHECK_NE(opener_index, WebStateList::kInvalidIndex);
-      user_data_manager->AddSerializableData(@(opener_index), kOpenerIndexKey);
-      user_data_manager->AddSerializableData(@(opener.navigation_index),
-                                             kOpenerNavigationIndexKey);
-    } else {
-      user_data_manager->AddSerializableData([NSNull null], kOpenerIndexKey);
-      user_data_manager->AddSerializableData([NSNull null],
-                                             kOpenerNavigationIndexKey);
-    }
-
-    [serialized_session addObject:web_state->BuildSessionStorage()];
-  }
-
-  NSUInteger selectedIndex =
-      web_state_list->active_index() != WebStateList::kInvalidIndex
-          ? static_cast<NSUInteger>(web_state_list->active_index())
-          : static_cast<NSUInteger>(NSNotFound);
-
-  return [[SessionWindowIOS alloc] initWithSessions:[serialized_session copy]
-                                      selectedIndex:selectedIndex];
-}
-
-void DeserializeWebStateList(WebStateList* web_state_list,
-                             SessionWindowIOS* session_window,
-                             const WebStateFactory& web_state_factory) {
-  web_state_list->PerformBatchOperation(
-      base::BindOnce(&DeserializeWebStateListHelper,
-                     base::Unretained(session_window), web_state_factory));
-}