Allow use of the chrome trace categories string from the tracing ui internals.

content/browser/trace_controller_impl.h

 // Copyright (c) 2012 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_TRACE_CONTROLLER_IMPL_H_
 #define CONTENT_BROWSER_TRACE_CONTROLLER_IMPL_H_
 
 #include <set>
 #include <string>
 #include <vector>
@@ skipping 10 matching lines @@
 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);
 
   // Get set of known categories. This can change as new code paths are reached.
   // If true is returned, subscriber->OnKnownCategoriesCollected will be called
-  // when once the categories are retrieved from child processes.
+  // once the categories are retrieved from child processes.
   bool GetKnownCategoriesAsync(TraceSubscriber* subscriber);
 
   // Same as above, but specifies which categories to trace.
   // If both included_categories and excluded_categories are empty,
   //   all categories are traced.
   // Else if included_categories is non-empty, only those are traced.
   // Else if excluded_categories is non-empty, everything but those are traced.
   bool BeginTracing(TraceSubscriber* subscriber,
                     const std::vector<std::string>& included_categories,
                     const std::vector<std::string>& excluded_categories);
 
   // TraceController implementation:
-  virtual bool BeginTracing(TraceSubscriber* subscriber) OVERRIDE;
   virtual bool BeginTracing(TraceSubscriber* subscriber,
                             const std::string& categories) OVERRIDE;
   virtual  bool EndTracingAsync(TraceSubscriber* subscriber) OVERRIDE;
   virtual bool GetTraceBufferPercentFullAsync(
       TraceSubscriber* subscriber) OVERRIDE;
   virtual void CancelSubscriber(TraceSubscriber* subscriber) OVERRIDE;
 
  private:
   typedef std::set<scoped_refptr<TraceMessageFilter> > FilterMap;
 
@@ skipping 47 matching lines @@
   std::vector<std::string> included_categories_;
   std::vector<std::string> excluded_categories_;
 
   DISALLOW_COPY_AND_ASSIGN(TraceControllerImpl);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_BROWSER_TRACE_CONTROLLER_IMPL_H_