Add support for TraceEvent before the native library is loaded.

content/browser/tracing/tracing_controller_impl.h

Index: content/browser/tracing/tracing_controller_impl.h
diff --git a/content/browser/tracing/tracing_controller_impl.h b/content/browser/tracing/tracing_controller_impl.h
index 330b9287466a8f7b597d1e15c2199a0d89c3ddc6..dc442c1bdb56cf80ed3989656639ea05d7effe27 100644
--- a/content/browser/tracing/tracing_controller_impl.h
+++ b/content/browser/tracing/tracing_controller_impl.h
@@ -9,12 +9,18 @@
 #include <string>
 #include <vector>
 
+#include "base/callback.h"
+#include "base/files/file_path.h"
 #include "base/lazy_instance.h"
 #include "content/public/browser/tracing_controller.h"
 
 namespace base {
 class RefCountedString;
 class RefCountedMemory;
+
+namespace debug {
+class TraceLog;
+}
 }
 
 namespace content {
@@ -24,6 +30,9 @@ class TracingUI;
 
 class TracingControllerImpl : public TracingController {
  public:
+  typedef base::Callback<
+      void (base::debug::TraceLog*)> DisableRecordingCallback;
+
   static TracingControllerImpl* GetInstance();
 
   // TracingController implementation.
@@ -53,6 +62,8 @@ class TracingControllerImpl : public TracingController {
   void RegisterTracingUI(TracingUI* tracing_ui);
   void UnregisterTracingUI(TracingUI* tracing_ui);
 
+  void SetDisableRecordingCallback(const DisableRecordingCallback& callback);
+
  private:
   typedef std::set<scoped_refptr<TraceMessageFilter> > TraceMessageFilterSet;
 
@@ -171,6 +182,8 @@ class TracingControllerImpl : public TracingController {
   std::set<TracingUI*> tracing_uis_;
   scoped_refptr<TraceDataSink> trace_data_sink_;
   scoped_refptr<TraceDataSink> monitoring_data_sink_;
+  DisableRecordingCallback disable_recording_callback_;
+
   DISALLOW_COPY_AND_ASSIGN(TracingControllerImpl);
 };