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

content/public/browser/speech_recognition_session_config.cc

 // 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.
 
 #include "content/public/browser/speech_recognition_session_config.h"
 
 namespace {
 const uint32_t kDefaultMaxHypotheses = 1;
 }
 
 namespace content {
 
 SpeechRecognitionSessionConfig::SpeechRecognitionSessionConfig()
     : is_legacy_api(true),
       filter_profanities(false),
       continuous(false),
       interim_results(false),
       max_hypotheses(kDefaultMaxHypotheses) {
 }
 
+SpeechRecognitionSessionConfig::SpeechRecognitionSessionConfig(
+    const SpeechRecognitionSessionConfig& other) = default;
+
 SpeechRecognitionSessionConfig::~SpeechRecognitionSessionConfig() {
 }
 
 }  // namespace content