Change sync primitives ownership for audio rendering.

content/browser/renderer_host/media/audio_sync_reader.h

 // 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.
 
 #ifndef CONTENT_BROWSER_RENDERER_HOST_MEDIA_AUDIO_SYNC_READER_H_
 #define CONTENT_BROWSER_RENDERER_HOST_MEDIA_AUDIO_SYNC_READER_H_
 
 #include <stddef.h>
 #include <stdint.h>
+#include <memory>
 
 #include "base/macros.h"
 #include "base/process/process.h"
 #include "base/sync_socket.h"
 #include "base/synchronization/lock.h"
 #include "base/time/time.h"
 #include "build/build_config.h"
 #include "media/audio/audio_output_controller.h"
 #include "media/base/audio_bus.h"
 
 #if defined(OS_POSIX)
 #include "base/file_descriptor_posix.h"
 #endif
 
 namespace base {
 class SharedMemory;
 }
 
 namespace content {
 
 // A AudioOutputController::SyncReader implementation using SyncSocket. This
 // is used by AudioOutputController to provide a low latency data source for
 // transmitting audio packets between the browser process and the renderer
 // process.
 class AudioSyncReader : public media::AudioOutputController::SyncReader {
  public:
-  AudioSyncReader(base::SharedMemory* shared_memory,
-                  const media::AudioParameters& params);
+  ~AudioSyncReader() override;
 
-  ~AudioSyncReader() override;
+  // Returns null on failure.
+  static std::unique_ptr<AudioSyncReader> Create(
+      const media::AudioParameters& params);
+
+  base::SharedMemory* shared_memory() const { return shared_memory_.get(); }
+  base::CancelableSyncSocket* foreign_socket() const {
+    return foreign_socket_.get();
+  }
 
   // media::AudioOutputController::SyncReader implementations.
   void UpdatePendingBytes(uint32_t bytes, uint32_t frames_skipped) override;
   void Read(media::AudioBus* dest) override;
   void Close() override;
 
-  bool Init();
-  bool PrepareForeignSocket(base::ProcessHandle process_handle,
-                            base::SyncSocket::TransitDescriptor* descriptor);
+ private:
+  AudioSyncReader(const media::AudioParameters& params,
+                  std::unique_ptr<base::SharedMemory> shared_memory,
+                  std::unique_ptr<base::CancelableSyncSocket> socket,
+                  std::unique_ptr<base::CancelableSyncSocket> foreign_socket);
 
- private:
   // Blocks until data is ready for reading or a timeout expires.  Returns false
   // if an error or timeout occurs.
   bool WaitUntilDataIsReady();
 
-  const base::SharedMemory* const shared_memory_;
+  std::unique_ptr<base::SharedMemory> shared_memory_;
 
   // Mutes all incoming samples. This is used to prevent audible sound
   // during automated testing.
   const bool mute_audio_;
 
   // Socket for transmitting audio data.
   std::unique_ptr<base::CancelableSyncSocket> socket_;
 
-  // Socket to be used by the renderer. The reference is released after
-  // PrepareForeignSocketHandle() is called and ran successfully.
+  // Socket to be used by the renderer.
   std::unique_ptr<base::CancelableSyncSocket> foreign_socket_;
 
   // Shared memory wrapper used for transferring audio data to Read() callers.
   std::unique_ptr<media::AudioBus> output_bus_;
 
   // Maximum amount of audio data which can be transferred in one Read() call.
   const int packet_size_;
 
   // Track the number of times the renderer missed its real-time deadline and
   // report a UMA stat during destruction.
   size_t renderer_callback_count_;
   size_t renderer_missed_callback_count_;
   size_t trailing_renderer_missed_callback_count_;
 
   // The maximum amount of time to wait for data from the renderer.  Calculated
   // from the parameters given at construction.
   const base::TimeDelta maximum_wait_time_;
 
   // The index of the audio buffer we're expecting to be sent from the renderer;
   // used to block with timeout for audio data.
   uint32_t buffer_index_;
 
   DISALLOW_COPY_AND_ASSIGN(AudioSyncReader);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_BROWSER_RENDERER_HOST_MEDIA_AUDIO_SYNC_READER_H_