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

content/public/browser/tracing_controller.h

Index: content/public/browser/tracing_controller.h
diff --git a/content/public/browser/tracing_controller.h b/content/public/browser/tracing_controller.h
index 5b3eb4e4873abf6930d398294003aa0ef84c4098..beb0671bc1fb397d7ea7ddb91019642936e57465 100644
--- a/content/public/browser/tracing_controller.h
+++ b/content/public/browser/tracing_controller.h
@@ -163,7 +163,7 @@ class TracingController {
   // Get the maximum across processes of trace buffer percent full state.
   // When the TraceBufferPercentFull value is determined, the callback is
   // called.
-  typedef base::Callback<void(float)> GetTraceBufferPercentFullCallback;
+  typedef base::Callback<void(float, size_t)> GetTraceBufferPercentFullCallback;
   virtual bool GetTraceBufferPercentFull(
       const GetTraceBufferPercentFullCallback& callback) = 0;