Use container::back() and container::pop_back() for content.

content/browser/indexed_db/indexed_db_database.cc

 // Copyright (c) 2013 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 "content/browser/indexed_db/indexed_db_database.h"
 
 #include <math.h>
 
 #include <limits>
 #include <memory>
@@ skipping 1906 matching lines @@
     pending_second_half_open_->callbacks()->OnError(
         IndexedDBDatabaseError(blink::WebIDBDatabaseExceptionAbortError,
                                "The connection was closed."));
     pending_second_half_open_.reset();
   }
 
   ProcessPendingCalls();
 
   // TODO(jsbell): Add a test for the pending_open_calls_ cases below.
   if (!ConnectionCount() && pending_open_calls_.empty() &&
-      !pending_delete_calls_.size()) {
+      pending_delete_calls_.empty()) {
     DCHECK(transactions_.empty());
     backing_store_ = NULL;
     factory_->ReleaseDatabase(identifier_, forced);
   }
 }
 
 void IndexedDBDatabase::CreateObjectStoreAbortOperation(
     int64_t object_store_id,
     IndexedDBTransaction* transaction) {
   DCHECK(!transaction);
@@ skipping 12 matching lines @@
 
 void IndexedDBDatabase::VersionChangeAbortOperation(
     int64_t previous_version,
     IndexedDBTransaction* transaction) {
   DCHECK(!transaction);
   IDB_TRACE("IndexedDBDatabase::VersionChangeAbortOperation");
   metadata_.version = previous_version;
 }
 
 }  // namespace content