fallback to null sink in WebAudioSourceProvider::Initialize() + UMA stats for device status

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 b9c9aae5f7568293f452961cac927b9c28762a56..c7651445a10ebb19715979d6677180aaae18ac59 100644
--- a/tools/metrics/histograms/histograms.xml
+++ b/tools/metrics/histograms/histograms.xml
@@ -23812,6 +23812,15 @@ http://cs/file:chrome/histograms.xml - but prefer this file for new entries.
   </summary>
 </histogram>
 
+<histogram name="Media.Audio.Render.OutputDeviceStatus"
+    enum="OutputDeviceStatus">
+  <owner>olka@chromium.org</owner>
+  <owner>dalecurtis@chromium.org</owner>
+  <summary>
+    Device status received in response to device authorization request.
+  </summary>
+</histogram>
+
 <histogram
     name="Media.Audio.Render.SinkCache.GetOutputDeviceInfoCacheUtilization"
     enum="GetOutputDeviceInfoCacheHit">
@@ -25639,6 +25648,16 @@ http://cs/file:chrome/histograms.xml - but prefer this file for new entries.
   </summary>
 </histogram>
 
+<histogram name="Media.WebAudioSourceProvider.SinkStatus"
+    enum="OutputDeviceStatus">
+  <owner>olka@chromium.org</owner>
+  <owner>dalecurtis@chromium.org</owner>
+  <summary>
+    Status of audio sink provided to WebMediaPlayer. If not OK, null sink will
+    be used for audio output instead.
+  </summary>
+</histogram>
+
 <histogram name="Media.WindowsCoreAudioInput" enum="BooleanSuccess">
   <owner>henrika@chromium.org</owner>
   <summary>
@@ -96483,6 +96502,14 @@ value.
   <int value="10" label="Hide for now"/>
 </enum>
 
+<enum name="OutputDeviceStatus" type="int">
+  <int value="0" label="Ok"/>
+  <int value="1" label="Not found"/>
+  <int value="2" label="Not authorized"/>
+  <int value="3" label="Authorization timed out"/>
+  <int value="4" label="Internal error"/>
+</enum>
+
 <enum name="OverscrollMode" type="int">
   <summary>Direction of the overscroll gesture.</summary>
   <int value="1" label="North">Scrolled from bottom towards top</int>