Implement Linux audio capturer.

remoting/host/audio_capturer_linux.h

Index: remoting/host/audio_capturer_linux.h
diff --git a/remoting/host/audio_capturer_linux.h b/remoting/host/audio_capturer_linux.h
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index 0000000000000000000000000000000000000000..4572e6ac65cd1a0fd1469f9df7e8a09305612db7
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+++ b/remoting/host/audio_capturer_linux.h
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+// 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 REMOTING_HOST_AUDIO_CAPTURER_LINUX_H_
+#define REMOTING_HOST_AUDIO_CAPTURER_LINUX_H_
+
+#include "remoting/host/audio_capturer.h"
+
+#include "base/message_loop.h"
+#include "base/time.h"
+#include "base/timer.h"
+
+class FilePath;
+
+namespace remoting {
+
+class AudioCapturerLinux : public AudioCapturer,
+                           public MessageLoopForIO::Watcher {
+ public:
+  explicit AudioCapturerLinux(const FilePath& pipe_name);
+  virtual ~AudioCapturerLinux();
+
+  // AudioCapturer interface.
+  virtual bool Start(const PacketCapturedCallback& callback) OVERRIDE;
+  virtual void Stop() OVERRIDE;
+  virtual bool IsRunning() OVERRIDE;
+
+  // MessageLoopForIO::Watcher interface.
+  virtual void OnFileCanReadWithoutBlocking(int fd) OVERRIDE;
+  virtual void OnFileCanWriteWithoutBlocking(int fd) OVERRIDE;
+
+ private:
+  void StartTimer();
+  void DoCapture();
+  void Sleep();
+
+  int pipe_fd_;
+  base::RepeatingTimer<AudioCapturerLinux> timer_;
+  PacketCapturedCallback callback_;
+
+  // Time when capturing was started.
+  base::TimeTicks started_time_;
+
+  // Time of the last capture measured in samples relative to the beginning of
+  // the stream.
+  int64 last_capture_time_samples_;
+
+  MessageLoopForIO::FileDescriptorWatcher file_descriptor_watcher_;
+
+  DISALLOW_COPY_AND_ASSIGN(AudioCapturerLinux);
+};
+
+}  // namespace remoting
+
+#endif  // REMOTING_HOST_AUDIO_CAPTURER_LINUX_H_