UMA stats for AudioRendererSinkCache utilization.

content/renderer/media/audio_renderer_sink_cache_impl.cc

Index: content/renderer/media/audio_renderer_sink_cache_impl.cc
diff --git a/content/renderer/media/audio_renderer_sink_cache_impl.cc b/content/renderer/media/audio_renderer_sink_cache_impl.cc
index 9fef7d0937b1dc594ee067d45f10a1ef6363b2ae..4e3df4c71e1617ce8a0d79715103869dc41ce118 100644
--- a/content/renderer/media/audio_renderer_sink_cache_impl.cc
+++ b/content/renderer/media/audio_renderer_sink_cache_impl.cc
@@ -7,6 +7,7 @@
 #include "base/bind.h"
 #include "base/location.h"
 #include "base/memory/ptr_util.h"
+#include "base/metrics/histogram_macros.h"
 #include "base/synchronization/lock.h"
 #include "base/threading/thread_task_runner_handle.h"
 #include "content/renderer/media/audio_device_factory.h"
@@ -88,6 +89,8 @@ media::OutputDeviceInfo AudioRendererSinkCacheImpl::GetSinkInfo(
       DVLOG(1) << "GetSinkInfo: address: " << cache_iter->sink.get()
                << " - reused a cached sink.";
 
+      UMA_HISTOGRAM_BOOLEAN("Media.Audio.SinkCache.GetOutputDeviceInfoHit",
+                            true);
       return cache_iter->sink->GetOutputDeviceInfo();
     }
 
@@ -103,6 +106,8 @@ media::OutputDeviceInfo AudioRendererSinkCacheImpl::GetSinkInfo(
     cache_.push_back(cache_entry);
   }
 
+  UMA_HISTOGRAM_BOOLEAN("Media.Audio.SinkCache.GetOutputDeviceInfoHit", false);

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

It would be nice to have the session ID case in its own bucket.

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

Done.

+
   // Schedule it for deletion.
   DeleteLaterIfUnused(cache_entry.sink.get());
 
@@ -118,6 +123,8 @@ scoped_refptr<media::AudioRendererSink> AudioRendererSinkCacheImpl::GetSink(
     int source_render_frame_id,
     const std::string& device_id,
     const url::Origin& security_origin) {
+  UMA_HISTOGRAM_BOOLEAN("Media.Audio.SinkCache.UsedForSinkCreation", true);

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

False is never recorded?

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

Recorded in AudioDeviceFactory

+
   base::AutoLock auto_lock(cache_lock_);
 
   auto cache_iter =
@@ -130,6 +137,8 @@ scoped_refptr<media::AudioRendererSink> AudioRendererSinkCacheImpl::GetSink(
              << " - found unused cached sink, reusing it.";
 
     cache_iter->used = true;
+    UMA_HISTOGRAM_BOOLEAN("Media.Audio.SinkCache.InfoSinkReusedForOutput",

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

I don't understand this histogram. Seems to record true when created and cached
sink is used, then records false when sink is deleted. What's the purpose here?

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

Discussed offline.

+                          true);
     return cache_iter->sink;
   }
 
@@ -205,8 +214,11 @@ void AudioRendererSinkCacheImpl::DeleteSink(
 
     // To stop the sink before deletion if it's not used, we need to hold
     // a ref to it.
-    if (!cache_iter->used)
+    if (!cache_iter->used) {
       sink_to_stop = cache_iter->sink;
+      UMA_HISTOGRAM_BOOLEAN("Media.Audio.SinkCache.InfoSinkReusedForOutput",
+                            false);
+    }
 
     cache_.erase(cache_iter);
     DVLOG(1) << "DeleteSink: address: " << sink_ptr;