Use TracingController for startup tracing

content/browser/tracing/trace_controller_impl.h

Index: content/browser/tracing/trace_controller_impl.h
diff --git a/content/browser/tracing/trace_controller_impl.h b/content/browser/tracing/trace_controller_impl.h
index 087b10c349c00056895145c6aa5018b71cf4f900..c058a04df15d6afc992bb5e0444ef9d3852f9a84 100644
--- a/content/browser/tracing/trace_controller_impl.h
+++ b/content/browser/tracing/trace_controller_impl.h
@@ -22,11 +22,6 @@ class TraceControllerImpl : public TraceController {
  public:
   static TraceControllerImpl* GetInstance();
 
-  // Called on the main thread of the browser process to initialize
-  // startup tracing.
-  void InitStartupTracing(const CommandLine& command_line);
-  bool is_tracing_startup() const { return is_tracing_startup_; }
-
   // TraceController implementation:
   virtual bool BeginTracing(TraceSubscriber* subscriber,
                             const std::string& category_patterns,
@@ -95,7 +90,6 @@ class TraceControllerImpl : public TraceController {
   int pending_bpf_ack_count_;
   float maximum_bpf_;
   bool is_tracing_;
-  bool is_tracing_startup_;
   bool is_get_category_groups_;
   std::set<std::string> known_category_groups_;
   std::string watch_category_;