Revert: Internalize JSON chunk merging to trace_event.h API.

base/debug/trace_event.h

Index: base/debug/trace_event.h
diff --git a/base/debug/trace_event.h b/base/debug/trace_event.h
index ec1884414c5cfce71de49a370a9cc11fe93dc1a3..d5aa256dc15cb769c2de0a312eb5c2084f7f56ba 100644
--- a/base/debug/trace_event.h
+++ b/base/debug/trace_event.h
@@ -515,50 +515,6 @@ class TraceEvent {
 };
 
 
-// TraceResultBuffer collects and converts trace fragments returned by TraceLog
-// to JSON output.
-class TraceResultBuffer {
- public:
-  typedef base::Callback<void(const std::string&)> OutputCallback;
-
-  // If you don't need to stream JSON chunks out efficiently, and just want to
-  // get a complete JSON string after calling Finish, use this struct to collect
-  // JSON trace output.
-  struct SimpleOutput {
-    OutputCallback GetCallback();
-    void Append(const std::string& json_string);
-
-    // Do what you want with the json_output_ string after calling
-    // TraceResultBuffer::Finish.
-    std::string json_output;
-  };
-
-  TraceResultBuffer();
-  ~TraceResultBuffer();
-
-  // Set callback. The callback will be called during Start with the initial
-  // JSON output and during AddFragment and Finish with following JSON output
-  // chunks. The callback target must live past the last calls to
-  // TraceResultBuffer::Start/AddFragment/Finish.
-  void SetOutputCallback(OutputCallback json_chunk_callback);
-
-  // Start JSON output. This resets all internal state, so you can reuse
-  // the TraceResultBuffer by calling Start.
-  void Start();
-
-  // Call AddFragment 0 or more times to add trace fragments from TraceLog.
-  void AddFragment(const std::string& trace_fragment);
-
-  // When all fragments have been added, call Finish to complete the JSON
-  // formatted output.
-  void Finish();
-
- private:
-  OutputCallback output_callback_;
-  bool append_comma_;
-};
-
-
 class BASE_EXPORT TraceLog {
  public:
   // Flags for passing to AddTraceEvent.
@@ -593,9 +549,7 @@ class BASE_EXPORT TraceLog {
 
   // When enough events are collected, they are handed (in bulk) to
   // the output callback. If no callback is set, the output will be
-  // silently dropped. The callback must be thread safe. The string format is
-  // undefined. Use TraceResultBuffer to convert one or more trace strings to
-  // JSON.
+  // silently dropped. The callback must be thread safe.
   typedef RefCountedData<std::string> RefCountedString;
   typedef base::Callback<void(scoped_refptr<RefCountedString>)> OutputCallback;
   void SetOutputCallback(const OutputCallback& cb);