Merge M56: "Add audio only watch time metrics."

media/base/media_log.h

Index: media/base/media_log.h
diff --git a/media/base/media_log.h b/media/base/media_log.h
index cfcf05308925ca59373f6a8646e6394c609563c6..2be72840ab1c6367d180119118e6619ecf5c6a78 100644
--- a/media/base/media_log.h
+++ b/media/base/media_log.h
@@ -84,6 +84,12 @@ class MEDIA_EXPORT MediaLog : public base::RefCountedThreadSafe<MediaLog> {
   void SetBooleanProperty(const std::string& key, bool value);
 
   // Histogram names used for reporting; also double as MediaLog key names.
+  static const char kWatchTimeAudioAll[];
+  static const char kWatchTimeAudioMse[];
+  static const char kWatchTimeAudioEme[];
+  static const char kWatchTimeAudioSrc[];
+  static const char kWatchTimeAudioBattery[];
+  static const char kWatchTimeAudioAc[];
   static const char kWatchTimeAudioVideoAll[];
   static const char kWatchTimeAudioVideoMse[];
   static const char kWatchTimeAudioVideoEme[];