Report trace buffer usage as number of events, not only percentage

content/browser/tracing/trace_message_filter.h

Index: content/browser/tracing/trace_message_filter.h
diff --git a/content/browser/tracing/trace_message_filter.h b/content/browser/tracing/trace_message_filter.h
index 3d12d76d300d23f497517afcafa419adcf15511d..a18303238e1b8b084dfea5f25c411ffede2d0a2f 100644
--- a/content/browser/tracing/trace_message_filter.h
+++ b/content/browser/tracing/trace_message_filter.h
@@ -45,7 +45,7 @@ class TraceMessageFilter : public BrowserMessageFilter {
   void OnEndTracingAck(const std::vector<std::string>& known_categories);
   void OnCaptureMonitoringSnapshotAcked();
   void OnWatchEventMatched();
-  void OnTraceBufferPercentFullReply(float percent_full);
+  void OnTraceBufferPercentFullReply(float percent_full, size_t buffer_usage);
   void OnTraceDataCollected(const std::string& data);
   void OnMonitoringTraceDataCollected(const std::string& data);