Add support for TraceEvent before the native library is loaded.

content/browser/tracing/tracing_controller_impl.h

 // Copyright (c) 2013 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef CONTENT_BROWSER_TRACING_TRACING_CONTROLLER_IMPL_H_
 #define CONTENT_BROWSER_TRACING_TRACING_CONTROLLER_IMPL_H_
 
 #include <set>
 #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 content {
 
 class TraceMessageFilter;
 class TracingUI;
 
 class TracingControllerImpl : public TracingController {
  public:
+  typedef base::Callback<
+      void (base::trace_event::TraceLog*)> DisableRecordingCallback;
+
   static TracingControllerImpl* GetInstance();
 
   // TracingController implementation.
   bool GetCategories(const GetCategoriesDoneCallback& callback) override;
   bool EnableRecording(const base::trace_event::CategoryFilter& category_filter,
                        const base::trace_event::TraceOptions& trace_options,
                        const EnableRecordingDoneCallback& callback) override;
   bool DisableRecording(const scoped_refptr<TraceDataSink>& sink) override;
   bool EnableMonitoring(
       const base::trace_event::CategoryFilter& category_filter,
@@ skipping 10 matching lines @@
   bool GetTraceBufferUsage(
       const GetTraceBufferUsageCallback& callback) override;
   bool SetWatchEvent(const std::string& category_name,
                      const std::string& event_name,
                      const WatchEventCallback& callback) override;
   bool CancelWatchEvent() override;
 
   void RegisterTracingUI(TracingUI* tracing_ui);
   void UnregisterTracingUI(TracingUI* tracing_ui);
 
+  void SetDisableRecordingCallback(const DisableRecordingCallback& callback);
+
  private:
   typedef std::set<scoped_refptr<TraceMessageFilter> > TraceMessageFilterSet;
 
   friend struct base::DefaultLazyInstanceTraits<TracingControllerImpl>;
   friend class TraceMessageFilter;
 
   TracingControllerImpl();
   ~TracingControllerImpl() override;
 
   bool can_enable_recording() const {
@@ skipping 99 matching lines @@
   GetTraceBufferUsageCallback pending_trace_buffer_usage_callback_;
 
   std::string watch_category_name_;
   std::string watch_event_name_;
   WatchEventCallback watch_event_callback_;
 
   std::set<std::string> known_category_groups_;
   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);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_BROWSER_TRACING_TRACING_CONTROLLER_IMPL_H_