Reland the CL 8162015.

media/audio/linux/audio_manager_linux.h

Index: media/audio/linux/audio_manager_linux.h
diff --git a/media/audio/linux/audio_manager_linux.h b/media/audio/linux/audio_manager_linux.h
index 77ea48154321f33947b76b6ebd207d81dd27bd8d..ed08a1a270acbeedc85f389a29c799c71219d767 100644
--- a/media/audio/linux/audio_manager_linux.h
+++ b/media/audio/linux/audio_manager_linux.h
@@ -42,8 +42,22 @@ class MEDIA_EXPORT AudioManagerLinux : public AudioManagerBase {
   virtual ~AudioManagerLinux();
 
  private:
-  // Helper method to query if there is any valid input device
-  bool HasAnyValidAudioInputDevice(void** hint);
+  enum StreamType {
+    kStreamPlayback = 0,
+    kStreamCapture,
+  };
+
+  // Gets a list of available ALSA input devices.
+  void GetAlsaAudioInputDevices(media::AudioDeviceNames* device_names);
+
+  // Gets the ALSA devices' names and ids.
+  void GetAlsaDevicesInfo(void** hint, media::AudioDeviceNames* device_names);
+
+  // Checks if the specific ALSA device is available.
+  bool IsAlsaDeviceAvailable(const char* device_name);
+
+  // Returns true if a device is present for the given stream type.
+  bool HasAnyAlsaAudioDevice(StreamType stream);
 
   scoped_ptr<AlsaWrapper> wrapper_;