Add UMA stats for silence AudioInputController.

media/audio/audio_input_controller.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 MEDIA_AUDIO_AUDIO_INPUT_CONTROLLER_H_
 #define MEDIA_AUDIO_AUDIO_INPUT_CONTROLLER_H_
 
 #include <string>
 #include "base/atomicops.h"
 #include "base/callback.h"
@@ skipping 228 matching lines @@
  protected:
   friend class base::RefCountedThreadSafe<AudioInputController>;
 
   // Internal state of the source.
   enum State {
     CREATED,
     RECORDING,
     CLOSED
   };
 
+#if defined(AUDIO_POWER_MONITORING)
+  // Used to log a silence report (see OnData).
+  // Elements in this enum should not be deleted or rearranged; the only
+  // permitted operation is to add new elements before SILENCE_STATE_MAX and
+  // update SILENCE_STATE_MAX.
+  enum SilenceState {
+    SILENCE_STATE_NO_MEASUREMENT = 0,
+    SILENCE_STATE_ONLY_AUDIO = 1,
+    SILENCE_STATE_ONLY_SILENCE = 2,
+    SILENCE_STATE_AUDIO_AND_SILENCE = 3,
+    SILENCE_STATE_MAX = SILENCE_STATE_AUDIO_AND_SILENCE
+  };
+#endif
+
   AudioInputController(EventHandler* handler,
                        SyncWriter* sync_writer,
                        UserInputMonitor* user_input_monitor);
   virtual ~AudioInputController();
 
   // Methods called on the audio thread (owned by the AudioManager).
   void DoCreate(AudioManager* audio_manager, const AudioParameters& params,
                 const std::string& device_id);
   void DoCreateForStream(AudioInputStream* stream_to_control);
   void DoRecord();
@@ skipping 11 matching lines @@
   // Method which ensures that OnError() is triggered when data recording
   // times out. Called on the audio thread.
   void DoCheckForNoData();
 
   // Helper method that stops, closes, and NULL:s |*stream_|.
   void DoStopCloseAndClearStream();
 
   void SetDataIsActive(bool enabled);
   bool GetDataIsActive();
 
+#if defined(AUDIO_POWER_MONITORING)
+  void LogSilenceState(SilenceState value);
+#endif
+
   // Gives access to the task runner of the creating thread.
   scoped_refptr<base::SingleThreadTaskRunner> creator_task_runner_;
 
   // The task runner of audio-manager thread that this object runs on.
   scoped_refptr<base::SingleThreadTaskRunner> task_runner_;
 
   // Contains the AudioInputController::EventHandler which receives state
   // notifications from this class.
   EventHandler* handler_;
 
@@ skipping 29 matching lines @@
 
   UserInputMonitor* user_input_monitor_;
 
 #if defined(AUDIO_POWER_MONITORING)
   // Scans audio samples from OnData() as input to compute audio levels.
   scoped_ptr<AudioPowerMonitor> audio_level_;
 
   // We need these to be able to feed data to the AudioPowerMonitor.
   media::AudioParameters audio_params_;
   base::TimeTicks last_audio_level_log_time_;
+
+  // The silence report sent as UMA stat at the end of a session.
+  SilenceState silence_state_;
 #endif
 
   size_t prev_key_down_count_;
 
   DISALLOW_COPY_AND_ASSIGN(AudioInputController);
 };
 
 }  // namespace media
 
 #endif  // MEDIA_AUDIO_AUDIO_INPUT_CONTROLLER_H_