Support sample rates up to 384 kHz.

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 ccf863c4f9014b5b20d094ff314123bb6c5a012e..f653828344796d62fcb71778498f962aa6f4984d 100644
--- a/tools/metrics/histograms/histograms.xml
+++ b/tools/metrics/histograms/histograms.xml
@@ -67654,6 +67654,19 @@ http://cs/file:chrome/histograms.xml - but prefer this file for new entries.
 </histogram>
 
 <histogram name="WebAudio.AudioBuffer.SampleRate" units="Hz">
+  <obsolete>
+    Replaced by SampleRate384kHz in Issue 644683 on 2016/10 due to higher
+    supported sample rates.
+  </obsolete>
+  <owner>rtoy@chromium.org</owner>
+  <owner>hongchan@chromium.org</owner>
+  <summary>
+    The sample rate (in Hz) requested by createBuffer(). Recorded for every call
+    to createBuffer(). Probably many (tens or hundreds) per page.
+  </summary>
+</histogram>
+
+<histogram name="WebAudio.AudioBuffer.SampleRate384kHz" units="Hz">
   <owner>rtoy@chromium.org</owner>
   <owner>hongchan@chromium.org</owner>
   <summary>
@@ -67663,6 +67676,21 @@ http://cs/file:chrome/histograms.xml - but prefer this file for new entries.
 </histogram>
 
 <histogram name="WebAudio.AudioBuffer.SampleRateRatio">
+  <obsolete>
+    Replaced by SampleRateRatio384kHz in Issue 644683 on 2016/10 due to higher
+    supported sample rates.
+  </obsolete>
+  <owner>rtoy@chromium.org</owner>
+  <owner>hongchan@chromium.org</owner>
+  <summary>
+    The ratio of the buffer sample rate from createBuffer() to the context
+    sample rate. This indicates if the buffer needs to be resampled.  Recorded
+    for every call to createBuffer().  Probably many (tens or hundreds) per
+    page.
+  </summary>
+</histogram>
+
+<histogram name="WebAudio.AudioBuffer.SampleRateRatio384kHz">
   <owner>rtoy@chromium.org</owner>
   <owner>hongchan@chromium.org</owner>
   <summary>
@@ -67776,6 +67804,20 @@ http://cs/file:chrome/histograms.xml - but prefer this file for new entries.
 </histogram>
 
 <histogram name="WebAudio.OfflineAudioContext.SampleRate" units="Hz">
+  <obsolete>
+    Replaced by SampleRate384kHz in Issue 644683 on 2016/10 due to higher
+    supported sample rates.
+  </obsolete>
+  <owner>rtoy@chromium.org</owner>
+  <owner>hongchan@chromium.org</owner>
+  <summary>
+    The sample rate (in Hz) specified for the offline audio context. Recorded
+    for every offline context created.  Probably only a few per page, but could
+    be potentially much more (thousands).
+  </summary>
+</histogram>
+
+<histogram name="WebAudio.OfflineAudioContext.SampleRate384kHz" units="Hz">
   <owner>rtoy@chromium.org</owner>
   <owner>hongchan@chromium.org</owner>
   <summary>