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

content/browser/devtools/protocol/tracing_handler.cc

Index: content/browser/devtools/protocol/tracing_handler.cc
diff --git a/content/browser/devtools/protocol/tracing_handler.cc b/content/browser/devtools/protocol/tracing_handler.cc
index 6e9fa55aa48cce3a0f1cd6cb22c0a734675ee6cd..fe187b84cfc5f5fdc2d00e12d7562bfd2dd9a000 100644
--- a/content/browser/devtools/protocol/tracing_handler.cc
+++ b/content/browser/devtools/protocol/tracing_handler.cc
@@ -142,8 +142,9 @@ void TracingHandler::OnRecordingEnabled(
   client_->SendStartResponse(command, StartResponse::Create());
 }
 
-void TracingHandler::OnBufferUsage(float usage) {
-  client_->BufferUsage(BufferUsageParams::Create()->set_value(usage));
+void TracingHandler::OnBufferUsage(float percent_full,
+                                   size_t approximate_event_count) {
+  client_->BufferUsage(BufferUsageParams::Create()->set_value(percent_full));
 }
 
 void TracingHandler::OnCategoriesReceived(