components: Add out-of-line copy ctors for complex classes.

components/data_usage/core/data_use.cc

 // Copyright 2015 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/data_usage/core/data_use.h"
 
 namespace data_usage {
 
 namespace {
 
@@ skipping 20 matching lines @@
                  int64_t rx_bytes)
     : url(url),
       request_start(request_start),
       first_party_for_cookies(first_party_for_cookies),
       tab_id(tab_id),
       connection_type(connection_type),
       mcc_mnc(mcc_mnc),
       tx_bytes(tx_bytes),
       rx_bytes(rx_bytes) {}
 
+DataUse::DataUse(const DataUse& other) = default;
+
 DataUse::~DataUse() {}
 
 bool DataUse::operator==(const DataUse& other) const {
   return AreNonByteCountFieldsEqual(*this, other) &&
          AreByteCountFieldsEqual(*this, other);
 }
 
 bool DataUse::CanCombineWith(const DataUse& other) const {
   return AreNonByteCountFieldsEqual(*this, other);
 }
 
 }  // namespace data_usage