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

content/browser/indexed_db/indexed_db_cursor.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_cursor.h"
 
 #include <stddef.h>
 #include <utility>
 #include <vector>
 
@@ skipping 149 matching lines @@
       default:
         NOTREACHED();
     }
     size_estimate += cursor_->key().size_estimate();
     size_estimate += cursor_->primary_key().size_estimate();
 
     if (size_estimate > max_size_estimate)
       break;
   }
 
-  if (!found_keys.size()) {
+  if (found_keys.empty()) {
     callbacks->OnSuccess(nullptr);
     return;
   }
 
   callbacks->OnSuccessWithPrefetch(
       found_keys, found_primary_keys, &found_values);
 }
 
 leveldb::Status IndexedDBCursor::PrefetchReset(int used_prefetches,
                                                int /* unused_prefetches */) {
@@ skipping 17 matching lines @@
 }
 
 void IndexedDBCursor::Close() {
   IDB_TRACE("IndexedDBCursor::Close");
   closed_ = true;
   cursor_.reset();
   saved_cursor_.reset();
 }
 
 }  // namespace content