Moving SwitchOutputDevice out of OutputDevice interface, eliminating OutputDevice

media/base/output_device_info.h

Index: media/base/output_device_info.h
diff --git a/media/base/output_device_info.h b/media/base/output_device_info.h
new file mode 100644
index 0000000000000000000000000000000000000000..c9c91ee66ee4e51b9ee4f7274bf9798e95ff1a22
--- /dev/null
+++ b/media/base/output_device_info.h
@@ -0,0 +1,68 @@
+// Copyright 2016 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 MEDIA_BASE_OUTPUT_DEVICE_INFO_H_
+#define MEDIA_BASE_OUTPUT_DEVICE_INFO_H_
+
+#include <string>
+
+#include "base/callback.h"
+#include "media/audio/audio_parameters.h"
+#include "media/base/media_export.h"
+
+namespace media {
+
+// Result of an audio output device switch operation
+enum OutputDeviceStatus {
+  OUTPUT_DEVICE_STATUS_OK = 0,
+  OUTPUT_DEVICE_STATUS_ERROR_NOT_FOUND,
+  OUTPUT_DEVICE_STATUS_ERROR_NOT_AUTHORIZED,
+  OUTPUT_DEVICE_STATUS_ERROR_INTERNAL,
+  OUTPUT_DEVICE_STATUS_LAST = OUTPUT_DEVICE_STATUS_ERROR_INTERNAL,
+};
+
+typedef base::Callback<void(OutputDeviceStatus)> OutputDeviceStatusCB;

[DaleCurtis, 2016/03/29 19:57:43]

use 'using' instead.

[o1ka, 2016/03/30 14:02:42]

Done.

+
+class MEDIA_EXPORT OutputDeviceInfo {
+ public:
+  // Use this constructor to initialize with "no info available" values.
+  OutputDeviceInfo();
+
+  // Use this constructor to indicate a specific error status of the device.
+  explicit OutputDeviceInfo(OutputDeviceStatus device_status);
+
+  OutputDeviceInfo(const std::string& device_id,
+                   OutputDeviceStatus device_status,
+                   const AudioParameters& output_params);
+
+  OutputDeviceInfo(const OutputDeviceInfo& other);
+
+  OutputDeviceInfo& operator=(const OutputDeviceInfo&);

[DaleCurtis, 2016/03/29 19:57:43]

There are a fair number of fields in this class. Chromium style typically avoids
assignment/pass by value except for primitive types. It seems we might want to
disallow copy and assign here and instead require that it's passed by
scoped_ptr? Is there a reason you went this route?

[o1ka, 2016/03/30 14:02:42]

OutputDeviceInfo is AudioParameters + int (device status) + std::string (device
ID). AudioParameters are returned by value everywhere, so it seems to be not a
big overhead to add the rest, and copying should be optimized(=omitted) by
compiler anyways. It seems not worth it to mess up with heap memory.

+
+  ~OutputDeviceInfo();
+
+  // Returns the device ID.
+  const std::string& device_id() const { return device_id_; }
+
+  // Returns the status of output device.
+  OutputDeviceStatus device_status() const { return device_status_; }
+
+  // Returns the device's audio output parameters.
+  // The return value is undefined if the device status (as returned by
+  // device_status()) is different from OUTPUT_DEVICE_STATUS_OK.
+  const AudioParameters& output_params() const { return output_params_; };
+
+  // Returns a human-readable string describing |*this|.  For debugging & test
+  // output only.
+  std::string AsHumanReadableString() const;
+
+ private:
+  std::string device_id_;
+  OutputDeviceStatus device_status_;
+  AudioParameters output_params_;
+};
+
+}  // namespace media
+
+#endif  // MEDIA_BASE_OUTPUT_DEVICE_INFO_H_