Add UMA histograms for WebAudio

third_party/WebKit/Source/modules/webaudio/BiquadFilterNode.cpp

Index: third_party/WebKit/Source/modules/webaudio/BiquadFilterNode.cpp
diff --git a/third_party/WebKit/Source/modules/webaudio/BiquadFilterNode.cpp b/third_party/WebKit/Source/modules/webaudio/BiquadFilterNode.cpp
index 9d6fda8af8499eea982ab6358dd81ddedece67a7..21364fe5ffc2ea4203aeec667baf04cde8d454f2 100644
--- a/third_party/WebKit/Source/modules/webaudio/BiquadFilterNode.cpp
+++ b/third_party/WebKit/Source/modules/webaudio/BiquadFilterNode.cpp
@@ -24,6 +24,7 @@
 
 #include "modules/webaudio/BiquadFilterNode.h"
 #include "modules/webaudio/AudioBasicProcessorHandler.h"
+#include "platform/Histogram.h"
 
 namespace blink {
 
@@ -114,6 +115,9 @@ bool BiquadFilterNode::setType(unsigned type)
     if (type > BiquadProcessor::Allpass)
         return false;
 
+    DEFINE_STATIC_LOCAL(SparseHistogram, filterTypeHistogram, ("WebAudio.BiquadFilter.Type"));
+    filterTypeHistogram.sample(type);
+
     getBiquadProcessor()->setType(static_cast<BiquadProcessor::FilterType>(type));
     return true;
 }