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

chrome/browser/media_galleries/fileapi/safe_media_metadata_parser.cc

 // Copyright 2014 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 "chrome/browser/media_galleries/fileapi/safe_media_metadata_parser.h"
 
 #include <utility>
 
 #include "base/memory/ptr_util.h"
 #include "chrome/browser/extensions/blob_reader.h"
@@ skipping 87 matching lines @@
       base::MakeUnique<std::vector<metadata::AttachedImage>>();
 
   content::BrowserThread::PostTask(
       content::BrowserThread::UI, FROM_HERE,
       base::Bind(callback_, false, base::Passed(&metadata_dictionary),
                  base::Passed(&attached_images)));
 }
 
 void SafeMediaMetadataParser::ParseMediaMetadataDone(
     bool parse_success,
-    std::unique_ptr<base::DictionaryValue> metadata_dictionary,
+    const base::DictionaryValue& metadata_dictionary,
     const std::vector<AttachedImage>& attached_images) {
   DCHECK_CURRENTLY_ON(content::BrowserThread::IO);
 
   utility_process_mojo_client_.reset();  // Terminate the utility process.
   media_data_source_.reset();
 
   // We need to make a scoped copy of this vector since it will be destroyed
   // at the end of the handler.
   std::unique_ptr<std::vector<metadata::AttachedImage>> attached_images_copy =
       base::MakeUnique<std::vector<metadata::AttachedImage>>(attached_images);
 
   content::BrowserThread::PostTask(
       content::BrowserThread::UI, FROM_HERE,
-      base::Bind(callback_, parse_success, base::Passed(&metadata_dictionary),
+      base::Bind(callback_, parse_success,
+                 base::Passed(metadata_dictionary.CreateDeepCopy()),
                  base::Passed(&attached_images_copy)));
 }
 
 void SafeMediaMetadataParser::StartBlobRequest(
     const extensions::mojom::MediaDataSource::ReadBlobCallback& callback,
     int64_t position,
     int64_t length) {
   DCHECK_CURRENTLY_ON(content::BrowserThread::IO);
 
   content::BrowserThread::PostTask(
@@ skipping 31 matching lines @@
 void SafeMediaMetadataParser::FinishBlobRequest(
     const extensions::mojom::MediaDataSource::ReadBlobCallback& callback,
     std::unique_ptr<std::string> data) {
   DCHECK_CURRENTLY_ON(content::BrowserThread::IO);
 
   if (utility_process_mojo_client_)
     callback.Run(std::vector<uint8_t>(data->begin(), data->end()));
 }
 
 }  // namespace metadata