Switch base::Value typemapping to be by value instead of by unique_ptr.

components/safe_json/safe_json_parser_impl.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 "components/safe_json/safe_json_parser_impl.h"
 
 #include "base/callback.h"
 #include "base/sequenced_task_runner.h"
 #include "base/threading/sequenced_task_runner_handle.h"
 #include "base/values.h"
@@ skipping 43 matching lines @@
 
   // Shut down the utility process.
   mojo_json_parser_.reset();
 
   caller_task_runner_->PostTask(
       FROM_HERE,
       base::Bind(&SafeJsonParserImpl::ReportResults, base::Unretained(this),
                  nullptr, "Connection error with the json parser process."));
 }
 
-void SafeJsonParserImpl::OnParseDone(std::unique_ptr<base::Value> result,
+void SafeJsonParserImpl::OnParseDone(const base::Optional<base::Value>& result,
                                      const base::Optional<std::string>& error) {
   DCHECK(io_thread_checker_.CalledOnValidThread());
 
   // Shut down the utility process.
   mojo_json_parser_.reset();
 
   // Call ReportResults() on caller's thread.
   caller_task_runner_->PostTask(
       FROM_HERE,
       base::Bind(&SafeJsonParserImpl::ReportResults, base::Unretained(this),
-                 base::Passed(&result), error.value_or("")));
+                 base::Passed(result ? result->CreateDeepCopy() : nullptr),
+                 error.value_or("")));
 }
 
 void SafeJsonParserImpl::ReportResults(std::unique_ptr<base::Value> parsed_json,
                                        const std::string& error) {
   DCHECK(caller_task_runner_->RunsTasksOnCurrentThread());
   if (error.empty() && parsed_json) {
     if (!success_callback_.is_null())
       success_callback_.Run(std::move(parsed_json));
   } else {
     if (!error_callback_.is_null())
       error_callback_.Run(error);
   }
 
   // The parsing is done whether an error occured or not, so this instance can
   // be cleaned up.
   delete this;
 }
 
 }  // namespace safe_json