gn/linux: warnings as errors, turn on Wextra

net/tools/quic/quic_in_memory_cache.h

 // Copyright (c) 2012 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_TOOLS_QUIC_QUIC_IN_MEMORY_CACHE_H_
 #define NET_TOOLS_QUIC_QUIC_IN_MEMORY_CACHE_H_
 
 #include <string>
 
 #include "base/containers/hash_tables.h"
@@ skipping 26 matching lines @@
     CLOSE_CONNECTION,  // Close the connection (sending the close packet).
     IGNORE_REQUEST,  // Do nothing, expect the client to time out.
   };
 
   // Container for response header/body pairs.
   class Response {
    public:
     Response() : response_type_(REGULAR_RESPONSE) {}
     ~Response() {}
 
-    const SpecialResponseType response_type() const { return response_type_; }
+    SpecialResponseType response_type() const { return response_type_; }
     const BalsaHeaders& headers() const { return headers_; }
     const base::StringPiece body() const { return base::StringPiece(body_); }
 
    private:
     friend class QuicInMemoryCache;
 
     void set_headers(const BalsaHeaders& headers) {
       headers_.CopyFrom(headers);
     }
     void set_body(base::StringPiece body) {
@@ skipping 52 matching lines @@
   // Cached responses.
   ResponseMap responses_;
 
   DISALLOW_COPY_AND_ASSIGN(QuicInMemoryCache);
 };
 
 }  // namespace tools
 }  // namespace net
 
 #endif  // NET_TOOLS_QUIC_QUIC_IN_MEMORY_CACHE_H_