Returning const ref instead of const value in CachedNetworkQuality::network_quality

net/base/network_quality_estimator.h

 // 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.
 
 #ifndef NET_BASE_NETWORK_QUALITY_ESTIMATOR_H_
 #define NET_BASE_NETWORK_QUALITY_ESTIMATOR_H_
 
 #include <stdint.h>
 
 #include <deque>
@@ skipping 178 matching lines @@
   };
 
   // CachedNetworkQuality stores the quality of a previously seen network.
   class NET_EXPORT_PRIVATE CachedNetworkQuality {
    public:
     explicit CachedNetworkQuality(const NetworkQuality& network_quality);
     CachedNetworkQuality(const CachedNetworkQuality& other);
     ~CachedNetworkQuality();
 
     // Returns the network quality associated with this cached entry.
-    const NetworkQuality network_quality() const { return network_quality_; }
+    const NetworkQuality& network_quality() const { return network_quality_; }
 
     // Returns true if this cache entry was updated before
     // |cached_network_quality|.
     bool OlderThan(const CachedNetworkQuality& cached_network_quality) const;
 
     // Time when this cache entry was last updated.
     const base::TimeTicks last_update_time_;
 
     // Quality of this cached network.
     const NetworkQuality network_quality_;
@@ skipping 223 matching lines @@
   const scoped_ptr<ExternalEstimateProvider> external_estimates_provider_;
 
   base::ThreadChecker thread_checker_;
 
   DISALLOW_COPY_AND_ASSIGN(NetworkQualityEstimator);
 };
 
 }  // namespace net
 
 #endif  // NET_BASE_NETWORK_QUALITY_ESTIMATOR_H_