MSE: Log buffered audio splice generation to media-internals

content/browser/media/media_internals.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "content/browser/media/media_internals.h"
 
 #include "base/metrics/histogram.h"
 #include "base/strings/string16.h"
 #include "base/strings/string_number_conversions.h"
 #include "base/strings/stringprintf.h"
@@ skipping 623 matching lines @@
   const size_t kMaxNumEvents = 128;
 
   // Do not save instantaneous events that happen frequently and have little
   // value in the future.
   if (event.type == media::MediaLogEvent::NETWORK_ACTIVITY_SET ||
       event.type == media::MediaLogEvent::BUFFERED_EXTENTS_CHANGED) {
     return;
   }
 
   auto& pending_events = pending_events_map_[process_id];
+
+  // Only save the most recent audio splicer statistics, if any. If the new
+  // event updates the statistics, then remove at most one previously saved
+  // statistics event.
+  if (event.type ==
+      media::MediaLogEvent::BUFFERED_AUDIO_SPLICE_STATISTICS_CHANGED) {
+    for (auto iter = pending_events.begin(); iter != pending_events.end();

[wolenetz, 2015/07/14 23:23:37]

This isn't a very efficient mechanism for enforcing at-most-one. wdyt?

[DaleCurtis, 2015/07/14 23:37:47]

I think you want to do something similar to what RendererMediaLog does and just
drop these events instead of saving them if media internals isn't open.

[xhwang, 2015/07/15 00:46:50]

Maybe it's time to drop all DEBUG logs when the UI is not open?

+         ++iter) {
+      if (iter->type ==
+          media::MediaLogEvent::BUFFERED_AUDIO_SPLICE_STATISTICS_CHANGED) {
+        pending_events.erase(iter);
+        break;
+      }
+    }
+  }
+
   // TODO(xhwang): Notify user that some old logs could have been truncated.
   // See http://crbug.com/498520
   if (pending_events.size() >= kMaxNumEvents)
     pending_events.pop_front();
   pending_events.push_back(event);
 }
 
 void MediaInternals::UpdateAudioLog(AudioLogUpdateType type,
                                     const std::string& cache_key,
                                     const std::string& function,
@@ skipping 15 matching lines @@
           audio_streams_cached_data_.GetDictionary(cache_key, &existing_dict));
       existing_dict->MergeDictionary(value);
     }
   }
 
   if (CanUpdate())
     SendUpdate(SerializeUpdate(function, value));
 }
 
 }  // namespace content