Internalize JSON chunk merging to trace_event.h API (retry).

content/browser/trace_controller.h

 // Copyright (c) 2011 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_H_
 #define CONTENT_BROWSER_TRACE_CONTROLLER_H_
 
 #include <set>
 #include <string>
 #include <vector>
 
 #include "base/debug/trace_event.h"
 #include "base/memory/singleton.h"
 #include "content/common/content_export.h"
 
 class TraceMessageFilter;
 
 // Objects interested in receiving trace data derive from TraceSubscriber.
 // See also: trace_message_filter.h
 // See also: child_trace_message_filter.h
 class CONTENT_EXPORT TraceSubscriber {
  public:
   // Called once after TraceController::EndTracingAsync.
   virtual void OnEndTracingComplete() = 0;
   // Called 0 or more times between TraceController::BeginTracing and
-  // OnEndTracingComplete.
-  virtual void OnTraceDataCollected(const std::string& json_events) = 0;
+  // OnEndTracingComplete. Use base::debug::TraceResultBuffer to convert one or
+  // more trace fragments to JSON.
+  virtual void OnTraceDataCollected(const std::string& trace_fragment) = 0;
   // Called once after TraceController::GetKnownCategoriesAsync.
   virtual void OnKnownCategoriesCollected(
       const std::set<std::string>& known_categories) {}
   virtual void OnTraceBufferPercentFullReply(float percent_full) {}
 };
 
 // TraceController is used on the browser processes to enable/disable
 // trace status and collect trace data. Only the browser UI thread is allowed
 // to interact with the TraceController object. All calls on the TraceSubscriber
 // happen on the UI thread.
@@ skipping 89 matching lines @@
 
   // Methods for use by TraceMessageFilter.
 
   // Passing as scoped_refptr so that the method can be run asynchronously as
   // a task safely (otherwise the TraceMessageFilter could be destructed).
   void AddFilter(TraceMessageFilter* filter);
   void RemoveFilter(TraceMessageFilter* filter);
   void OnEndTracingAck(const std::vector<std::string>& known_categories);
   void OnTraceDataCollected(
       const scoped_refptr<base::debug::TraceLog::RefCountedString>&
-          json_events_str_ptr);
+          events_str_ptr);
   void OnTraceBufferFull();
   void OnTraceBufferPercentFullReply(float percent_full);
 
   FilterMap filters_;
   TraceSubscriber* subscriber_;
   // Pending acks for EndTracingAsync:
   int pending_end_ack_count_;
   // Pending acks for GetTraceBufferPercentFullAsync:
   int pending_bpf_ack_count_;
   float maximum_bpf_;
   bool is_tracing_;
   bool is_get_categories_;
   std::set<std::string> known_categories_;
   std::vector<std::string> included_categories_;
   std::vector<std::string> excluded_categories_;
 
   DISALLOW_COPY_AND_ASSIGN(TraceController);
 };
 
 #endif  // CONTENT_BROWSER_TRACE_CONTROLLER_H_