Add support for TraceEvent before the native library is loaded.

content/browser/tracing/tracing_controller_impl.cc

Index: content/browser/tracing/tracing_controller_impl.cc
diff --git a/content/browser/tracing/tracing_controller_impl.cc b/content/browser/tracing/tracing_controller_impl.cc
index 480481fdb74b1151f55269cdc6324f1766721e49..10f9adc76f0270735fa81071d3630fa6435e4a49 100644
--- a/content/browser/tracing/tracing_controller_impl.cc
+++ b/content/browser/tracing/tracing_controller_impl.cc
@@ -319,6 +319,9 @@ void TracingControllerImpl::OnDisableRecordingDone() {
   pending_disable_recording_ack_count_ = trace_message_filters_.size() + 1;
   pending_disable_recording_filters_ = trace_message_filters_;
 
+  if (!disable_recording_callback_.is_null())
+    disable_recording_callback_.Run(TraceLog::GetInstance());
+
 #if defined(OS_CHROMEOS) || defined(OS_WIN)
   if (is_system_tracing_) {
     // Disable system tracing.
@@ -877,6 +880,11 @@ void TracingControllerImpl::UnregisterTracingUI(TracingUI* tracing_ui) {
   tracing_uis_.erase(it);
 }
 
+void TracingControllerImpl::SetDisableRecordingCallback(
+    const DisableRecordingCallback& callback) {
+  disable_recording_callback_ = callback;
+}
+
 void TracingControllerImpl::OnMonitoringStateChanged(bool is_monitoring) {
   if (is_monitoring_ == is_monitoring)
     return;