UMA stats for AudioRendererSinkCache utilization.

content/renderer/media/audio_device_factory.cc

 // 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.
 
 #include "content/renderer/media/audio_device_factory.h"
 
 #include <algorithm>
 
 #include "base/logging.h"
+#include "base/metrics/histogram_macros.h"
 #include "build/build_config.h"
 #include "content/common/content_constants_internal.h"
 #include "content/renderer/media/audio_input_message_filter.h"
 #include "content/renderer/media/audio_message_filter.h"
 #include "content/renderer/media/audio_renderer_mixer_manager.h"
 #include "content/renderer/render_thread_impl.h"
 #include "media/audio/audio_input_device.h"
 #include "media/audio/audio_output_device.h"
 #include "media/base/audio_latency.h"
 #include "media/base/audio_renderer_mixer_input.h"
@@ skipping 101 matching lines @@
                                           session_id, device_id,
                                           security_origin);
     if (device)
       return device;
   }
 
   if (IsMixable(source_type))
     return NewMixableSink(source_type, render_frame_id, session_id, device_id,
                           security_origin);
 
+  UMA_HISTOGRAM_BOOLEAN("Media.Audio.SinkCache.UsedForSinkCreation", false);

[Henrik Grunell, 2016/07/04 14:24:59]

Maybe add "Renderer" to be in line with other histogram names? E.g.
"Media.Audio.Renderer.SinkCache.UsedForSinkCreation".

[o1ka, 2016/07/06 13:17:30]

Done.

   return NewFinalAudioRendererSink(render_frame_id, session_id, device_id,
                                    security_origin);
 }
 
 // static
 scoped_refptr<media::SwitchableAudioRendererSink>
 AudioDeviceFactory::NewSwitchableAudioRendererSink(
     SourceType source_type,
     int render_frame_id,
     int session_id,
@@ skipping 68 matching lines @@
                                                device_id, security_origin);
     if (sink)
       return sink;
   }
 
   return NewOutputDevice(render_frame_id, session_id, device_id,
                          security_origin);
 }
 
 }  // namespace content