Tracing pre-filtering

base/trace_event/trace_event.h

Index: base/trace_event/trace_event.h
diff --git a/base/trace_event/trace_event.h b/base/trace_event/trace_event.h
index 250c161d46ce018ff316a0ee8ac8c44f0ba79e92..53395dc670c76adf51108c5ea9c6f44abc2443fe 100644
--- a/base/trace_event/trace_event.h
+++ b/base/trace_event/trace_event.h
@@ -78,6 +78,11 @@
             base::trace_event::TraceLog::ENABLED_FOR_EVENT_CALLBACK |    \
             base::trace_event::TraceLog::ENABLED_FOR_ETW_EXPORT))
 
+#define INTERNAL_TRACE_EVENT_CATEGORY_GROUP_ENABLED_FOR_FILTERING_MODE( \
+    category_group_enabled)                                             \
+  UNLIKELY(category_group_enabled&                                      \
+               base::trace_event::TraceLog::ENABLED_FOR_FILTERING)
+
 ////////////////////////////////////////////////////////////////////////////////
 // Implementation specific tracing API definitions.
 
@@ -185,6 +190,14 @@
 #define TRACE_EVENT_API_UPDATE_TRACE_EVENT_DURATION \
     base::trace_event::TraceLog::GetInstance()->UpdateTraceEventDuration
 
+// Call EndEvent on the filter for a filtered event.
+// void TRACE_EVENT_API_UPDATE_TRACE_EVENT_DURATION(
+//     const unsigned char* category_group_enabled,
+//     const char* name,
+//     base::trace_event::TraceEventHandle id)
+#define TRACE_EVENT_API_END_FILTERED_EVENT \
+  base::trace_event::TraceLog::GetInstance()->EndFilteredEvent
+
 // Adds a metadata event to the trace log. The |AppendValueAsTraceFormat| method
 // on the convertable value will be called at flush time.
 // TRACE_EVENT_API_ADD_METADATA_EVENT(
@@ -999,9 +1012,15 @@ class TRACE_EVENT_API_CLASS_EXPORT ScopedTracer {
   ScopedTracer() : p_data_(NULL) {}
 
   ~ScopedTracer() {
-    if (p_data_ && *data_.category_group_enabled)
+    if (p_data_ && *data_.category_group_enabled) {
       TRACE_EVENT_API_UPDATE_TRACE_EVENT_DURATION(
           data_.category_group_enabled, data_.name, data_.event_handle);
+      if (INTERNAL_TRACE_EVENT_CATEGORY_GROUP_ENABLED_FOR_FILTERING_MODE(
+              *data_.category_group_enabled)) {
+        TRACE_EVENT_API_END_FILTERED_EVENT(data_.category_group_enabled,
+                                           data_.name, data_.event_handle);
+      }
+    }
   }
 
   void Initialize(const unsigned char* category_group_enabled,