media-internals: Store updates when cannot update.

content/browser/media/media_internals.cc

Index: content/browser/media/media_internals.cc
diff --git a/content/browser/media/media_internals.cc b/content/browser/media/media_internals.cc
index 7f4d62ec96203080e2d9dc8065a1a2ff204c0560..ae4e67b82c0fe930f07a9099057bb8ef0f9a96df 100644
--- a/content/browser/media/media_internals.cc
+++ b/content/browser/media/media_internals.cc
@@ -321,7 +321,7 @@ void MediaInternals::MediaInternalsUMAHandler::Observe(
   // by both SavePlayerState & LogAndClearPlayersInRenderer from different
   // threads.
   // Using base::Unretained() on MediaInternalsUMAHandler is safe since
-  // it is owned by MediaInternals and share the same lifetime
+  // it is owned by MediaInternals and shares the same lifetime.
   BrowserThread::PostTask(
       BrowserThread::IO, FROM_HERE,
       base::Bind(&MediaInternalsUMAHandler::LogAndClearPlayersInRenderer,
@@ -450,6 +450,7 @@ void MediaInternals::MediaInternalsUMAHandler::LogAndClearPlayersInRenderer(
     ReportUMAForPipelineStatus(it->second);
     players_it->second.erase(it++);
   }
+  renderer_info_.erase(players_it);
 }
 
 MediaInternals* MediaInternals::GetInstance() {
@@ -497,6 +498,9 @@ void MediaInternals::OnMediaEvents(
 
     if (CanUpdate())
       SendUpdate(SerializeUpdate("media.onMediaEvent", &dict));
+    else
+      SaveUpdate(SerializeUpdate("media.onMediaEvent", &dict));
+
     uma_handler_->SavePlayerState(*event, render_process_id);
   }
 }
@@ -527,6 +531,14 @@ bool MediaInternals::CanUpdate() {
   return can_update_;
 }
 
+void MediaInternals::SendHistoricalMediaEvents() {
+  DCHECK_CURRENTLY_ON(BrowserThread::UI);
+  base::AutoLock auto_lock(lock_);
+  for (const auto& update : pending_updates_)
+    SendUpdate(update);
+  pending_updates_.clear();
+}
+
 void MediaInternals::SendAudioStreamData() {
   base::string16 audio_stream_update;
   {
@@ -601,6 +613,17 @@ void MediaInternals::SendUpdate(const base::string16& update) {
     update_callbacks_[i].Run(update);
 }
 
+void MediaInternals::SaveUpdate(const base::string16& update) {
+  DCHECK_CURRENTLY_ON(BrowserThread::IO);
+
+  static const size_t kMaxNumUpdates = 2048;

[DaleCurtis, 2015/06/09 16:41:32]

Usually just const at function scope.

[xhwang, 2015/06/09 20:37:57]

Done.

+
+  base::AutoLock auto_lock(lock_);
+  if (pending_updates_.size() >= kMaxNumUpdates)
+    pending_updates_.pop_front();
+  pending_updates_.push_back(update);
+}
+
 void MediaInternals::SendAudioLogUpdate(AudioLogUpdateType type,
                                         const std::string& cache_key,
                                         const std::string& function,