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

gin/dictionary.cc

 // Copyright 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 "gin/dictionary.h"
 
 namespace gin {
 
 Dictionary::Dictionary(v8::Isolate* isolate)
     : isolate_(isolate) {
 }
 
 Dictionary::Dictionary(v8::Isolate* isolate,
                        v8::Local<v8::Object> object)
     : isolate_(isolate),
       object_(object) {
 }
 
+Dictionary::Dictionary(const Dictionary& other) = default;
+
 Dictionary::~Dictionary() {
 }
 
 Dictionary Dictionary::CreateEmpty(v8::Isolate* isolate) {
   Dictionary dictionary(isolate);
   dictionary.object_ = v8::Object::New(isolate);
   return dictionary;
 }
 
 v8::Local<v8::Value> Converter<Dictionary>::ToV8(v8::Isolate* isolate,
                                                   Dictionary val) {
   return val.object_;
 }
 
 bool Converter<Dictionary>::FromV8(v8::Isolate* isolate,
                                    v8::Local<v8::Value> val,
                                    Dictionary* out) {
   if (!val->IsObject())
     return false;
   *out = Dictionary(isolate, v8::Local<v8::Object>::Cast(val));
   return true;
 }
 
 }  // namespace gin