Motown: Add examples/media_test, a command line media player app.

examples/media_test/media_test.h

+// Copyright 2015 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 EXAMPLES_MEDIA_TEST_MEDIA_TEST_H_
+#define EXAMPLES_MEDIA_TEST_MEDIA_TEST_H_
+
+#include "base/macros.h"
+#include "mojo/public/cpp/application/application_impl.h"
+#include "mojo/services/media/common/cpp/linear_transform.h"
+#include "mojo/services/media/common/interfaces/rate_control.mojom.h"
+#include "mojo/services/media/control/interfaces/media_factory.mojom.h"
+#include "mojo/services/media/control/interfaces/media_player.mojom.h"
+
+namespace mojo {
+namespace media {
+namespace examples {
+
+// Model for media test application.
+class MediaTest {
+ public:
+  using UpdateCallback = std::function<void()>;
+
+  static std::unique_ptr<MediaTest> Create(
+      mojo::ApplicationImpl* app,
+      const std::string& input_file_name);
+
+  ~MediaTest();
+
+  // Registers a callback signalling that the app should update its view.
+  void RegisterUpdateCallback(const UpdateCallback& callback);
+
+  // Starts playback.
+  void Play();
+
+  // Pauses playback.
+  void Pause();
+
+  // Seeks to the position indicated in nanoseconds from the start of the media.
+  void Seek(int64_t position_ns);
+
+  // Returns the current state of the player.
+  MediaState state() const;
+
+  // Returns the current presentation time in nanoseconds.
+  int64_t position_ns() const;
+
+  // Returns the current media metadata, if there is any.
+  const MediaMetadataPtr& metadata() const;
+
+ private:
+  MediaTest(mojo::ApplicationImpl* app, const std::string& input_file_name);
+
+  // Handles a status update from the player. When called with the default
+  // argument values, initiates status updates.
+  void HandleStatusUpdates(
+      uint64_t version = MediaPlayer::kInitialStatus,
+      MediaPlayerStatusPtr status = nullptr);
+
+  MediaPlayerPtr media_player_;
+  MediaState state_;
+  LinearTransform transform_ = LinearTransform(0, 1, 1, 0);

[johngro, 2016/03/22 16:56:35]

Assuming that local->media time is the forward transform here, this should be
initialized to (0, 0, 1, 0).  This way, no matter what local time reads, media
time will be 0 until the system is buffered and running.

Right now, this will end up reporting local time as media time until the system
receives its first update from the player.

[dalesat, 2016/03/22 19:59:39]

Done.

+  MediaMetadataPtr metadata_;
+  UpdateCallback update_callback_;
+
+  DISALLOW_COPY_AND_ASSIGN(MediaTest);
+};
+
+}  // namespace examples
+}  // namespace media
+}  // namespace mojo
+
+#endif  // EXAMPLES_MEDIA_TEST_MEDIA_TEST_H_