Remove all ReadingList entries on managed account signout.

components/reading_list/ios/reading_list_model_impl.cc

 // Copyright 2016 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 "components/reading_list/ios/reading_list_model_impl.h"
 
 #include "base/bind.h"
 #include "base/logging.h"
 #include "base/memory/ptr_util.h"
 #include "base/strings/string_util.h"
@@ skipping 128 matching lines @@
     if (storage_layer_) {
       storage_layer_->SaveEntry(entry);
     }
     for (auto& observer : observers_) {
       observer.ReadingListDidApplyChanges(this);
     }
   }
   DCHECK(unseen_entry_count_ == 0);
 }
 
+bool ReadingListModelImpl::DeleteAllEntries() {
+  DCHECK(CalledOnValidThread());
+  if (!loaded()) {
+    return false;
+  }
+  auto scoped_model_batch_updates = BeginBatchUpdates();
+  for (const auto& url : Keys()) {
+    RemoveEntryByURL(url);
+  }
+  return entries_->empty();
+}
+
 void ReadingListModelImpl::UpdateEntryStateCountersOnEntryRemoval(
     const ReadingListEntry& entry) {
   if (!entry.HasBeenSeen()) {
     unseen_entry_count_--;
   }
   if (entry.IsRead()) {
     read_entry_count_--;
   } else {
     unread_entry_count_--;
   }
@@ skipping 342 matching lines @@
 
 syncer::ModelTypeSyncBridge* ReadingListModelImpl::GetModelTypeSyncBridge() {
   if (!storage_layer_)
     return nullptr;
   return storage_layer_.get();
 }
 
 ReadingListModelStorage* ReadingListModelImpl::StorageLayer() {
   return storage_layer_.get();
 }