Convert utility process ParseMediaMetadata blob reading IPC to mojo

chrome/utility/media_galleries/media_metadata_parser.h

 // 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.
 
 #ifndef CHROME_UTILITY_MEDIA_GALLERIES_MEDIA_METADATA_PARSER_H_
 #define CHROME_UTILITY_MEDIA_GALLERIES_MEDIA_METADATA_PARSER_H_
 
 #include <memory>
 #include <string>
 #include <vector>
@@ skipping 18 matching lines @@
 // This class lives and operates on the utility thread of the utility process,
 // as we wish to sandbox potentially dangerous operations on user-provided data.
 class MediaMetadataParser {
  public:
   typedef extensions::api::media_galleries::MediaMetadata MediaMetadata;
   typedef base::Callback<
       void(const MediaMetadata& metadata,
            const std::vector<AttachedImage>& attached_images)>
   MetadataCallback;
 
-  // Does not take ownership of |source|. Caller is responsible for ensuring
-  // that |source| outlives this object.
-  MediaMetadataParser(media::DataSource* source, const std::string& mime_type,
+  MediaMetadataParser(std::unique_ptr<media::DataSource> source,
+                      const std::string& mime_type,
                       bool get_attached_images);
 
   ~MediaMetadataParser();
 
   // |callback| is called on same message loop.
   void Start(const MetadataCallback& callback);
 
  private:
   // Only accessed on |media_thread_| from this class.
-  media::DataSource* const source_;
+  std::unique_ptr<media::DataSource> source_;
 
   const std::string mime_type_;
 
   bool get_attached_images_;
 
   // Thread that blocking media parsing operations run on while the main thread
   // handles messages from the browser process.
   // TODO(tommycli): Replace with a reference to a WorkerPool if we ever use
   // this class in batch mode.
   std::unique_ptr<base::Thread> media_thread_;
 
   DISALLOW_COPY_AND_ASSIGN(MediaMetadataParser);
 };
 
 }  // namespace metadata
 
 #endif  // CHROME_UTILITY_MEDIA_GALLERIES_MEDIA_METADATA_PARSER_H_