Mixing audio with different latency requirements

tools/metrics/histograms/histograms.xml

Index: tools/metrics/histograms/histograms.xml
diff --git a/tools/metrics/histograms/histograms.xml b/tools/metrics/histograms/histograms.xml
index bc46ae630f07dc43b5a2ede866f028b3360112c5..01fec650d7d9816a070d19398ebc88544ab68b52 100644
--- a/tools/metrics/histograms/histograms.xml
+++ b/tools/metrics/histograms/histograms.xml
@@ -21054,6 +21054,64 @@ http://cs/file:chrome/histograms.xml - but prefer this file for new entries.
   </summary>
 </histogram>
 
+<histogram name="Media.Audio.Render.AudioInputsPerMixer.LatencyExact"
+    units="inputs">
+  <owner>olka@chromium.org</owner>
+  <summary>
+    Number of simultaneous inputs coming to the AudioRendererMixer rendering
+    audio with the latency of the exact value specified by the user. The value
+    is lifetime maximum logged on the mixer destruction. It is useful for
+    evaluating how mixing audio in renderer reduces the number of output audio
+    streams going from the renderer to the browser.
+  </summary>
+</histogram>
+
+<histogram name="Media.Audio.Render.AudioInputsPerMixer.LatencyInteractive"
+    units="inputs">
+  <owner>olka@chromium.org</owner>
+  <summary>
+    Number of simultaneous inputs coming to the AudioRendererMixer rendering
+    audio with interactive latency. The value is lifetime maximum logged on the
+    mixer destruction. It is useful for evaluating how mixing audio in renderer
+    reduces the number of output audio streams going from the renderer to the
+    browser.
+  </summary>
+</histogram>
+
+<histogram name="Media.Audio.Render.AudioInputsPerMixer.LatencyPlayback"
+    units="inputs">
+  <owner>olka@chromium.org</owner>
+  <summary>
+    Number of simultaneous inputs coming to the AudioRendererMixer rendering
+    audio with playback latency. The value is lifetime maximum logged on the
+    mixer destruction. It is useful for evaluating how mixing audio in renderer
+    reduces the number of output audio streams going from the renderer to the
+    browser.
+  </summary>
+</histogram>
+
+<histogram name="Media.Audio.Render.AudioInputsPerMixer.LatencyRtc"
+    units="inputs">
+  <owner>olka@chromium.org</owner>
+  <summary>
+    Number of simultaneous inputs coming to the AudioRendererMixer rendering
+    audio with real time latency. The value is lifetime maximum logged on the
+    mixer destruction. It is useful for evaluating how mixing audio in renderer
+    reduces the number of output audio streams going from the renderer to the
+    browser.
+  </summary>
+</histogram>
+
+<histogram name="Media.Audio.Render.AudioMixing.LatencyMap" units="subsets">
+  <owner>olka@chromium.org</owner>
+  <summary>
+    Subset of audio output latencies encountered during the renderer lifetime.
+    Logged on the renderer destruction. The values are bitsets where each bit
+    represents corresponding latency according to AudioLatency::LatencyType.
+    Useful for understanding usecases for audio output mixing in renderer.
+  </summary>
+</histogram>
+
 <histogram name="Media.Audio.Render.FramesRequested" units="frames">
   <owner>tommi@chromium.org</owner>
   <summary>