UMA stats for browser/renderer audio rendering buffer size mismatch.

content/renderer/media/audio_device_factory.h

Index: content/renderer/media/audio_device_factory.h
diff --git a/content/renderer/media/audio_device_factory.h b/content/renderer/media/audio_device_factory.h
index ee15a42006f68f3142c02edebb0ca284a24961ef..194ef95e206402ecd98c396d77fb0b2996b77296 100644
--- a/content/renderer/media/audio_device_factory.h
+++ b/content/renderer/media/audio_device_factory.h
@@ -11,6 +11,7 @@
 #include "base/macros.h"
 #include "base/memory/ref_counted.h"
 #include "content/common/content_export.h"
+#include "media/base/audio_latency.h"
 #include "media/base/output_device_info.h"
 
 namespace media {
@@ -48,6 +49,10 @@ class CONTENT_EXPORT AudioDeviceFactory {
     kSourceLast = kSourceWebAudioExact  // Only used for validation of format.
   };
 
+  // Maps the source type to the audio latency it requires.
+  static media::AudioLatency::LatencyType GetSourceLatencyType(
+      SourceType source);
+
   // Creates a sink for AudioRendererMixer.
   // |render_frame_id| refers to the RenderFrame containing the entity
   // producing the audio. If |session_id| is nonzero, it is used by the browser