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

base/debug/trace_event_impl.h

Index: base/debug/trace_event_impl.h
diff --git a/base/debug/trace_event_impl.h b/base/debug/trace_event_impl.h
index 6075e2dee78698a897ed2e5485d20a59de721edf..788213e767bbcf1b0ad83a70d95181a427decc6e 100644
--- a/base/debug/trace_event_impl.h
+++ b/base/debug/trace_event_impl.h
@@ -495,7 +495,11 @@ class BASE_EXPORT TraceLog {
   void RemoveEnabledStateObserver(EnabledStateObserver* listener);
   bool HasEnabledStateObserver(EnabledStateObserver* listener) const;
 
-  float GetBufferPercentFull() const;
+  struct BufferUsage {
+    float percent_full;
+    size_t approximate_event_count;
+  };
+  BufferUsage GetBufferUsage() const;
   bool BufferIsFull() const;
 
   // Not using base::Callback because of its limited by 7 parameters.
@@ -603,7 +607,6 @@ class BASE_EXPORT TraceLog {
   static void DeleteForTesting();
 
   // Allow tests to inspect TraceEvents.
-  size_t GetEventsSize() const { return logged_events_->Size(); }
   TraceEvent* GetEventByHandle(TraceEventHandle handle);
 
   void SetProcessID(int process_id);