[Tracing Clock Sync] Add TracingAgent interface in Chrome

content/public/browser/tracing_controller.h

 // Copyright 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_PUBLIC_BROWSER_TRACING_CONTROLLER_H_
 #define CONTENT_PUBLIC_BROWSER_TRACING_CONTROLLER_H_
 
 #include <set>
 #include <string>
 
@@ skipping 23 matching lines @@
   // have completed tracing and the data collection is over.
   // All methods are called on the UI thread.
   // Close method will be called exactly once and no methods will be
   // called after that.
   class CONTENT_EXPORT TraceDataSink
       : public base::RefCountedThreadSafe<TraceDataSink> {
    public:
     TraceDataSink();
 
     virtual void AddTraceChunk(const std::string& chunk) {}
-    virtual void SetSystemTrace(const std::string& data) {}
+
+    // Add a TracingAgent's trace to the data sink.
+    virtual void AddAgentTrace(const std::string& trace_label,
+                               const std::string& trace_data);
 
     // Notice that TracingController adds some default metadata when
     // StopTracing is called, which may override metadata that you would
     // set beforehand in case of key collision.
     virtual void AddMetadata(const base::DictionaryValue& data);
     virtual scoped_ptr<const base::DictionaryValue> GetMetadataCopy() const;
     virtual void SetMetadataFilterPredicate(
         const MetadataFilterPredicate& metadata_filter_predicate);
-    // TODO(prabhur) Replace all the Set* functions with a generic function:
-    // TraceDataSink::AppendAdditionalData(const std::string& name,
-    // const std::string& trace_data)
-    virtual void SetPowerTrace(const std::string& data) {}
     virtual void Close() {}
 
    protected:
     friend class base::RefCountedThreadSafe<TraceDataSink>;
+
+    // Get a map of TracingAgent's data, which is previously added by
+    // AddAgentTrace(). The map's key is the trace label and the map's value is
+    // the trace data.
+    virtual const std::map<std::string, std::string>& GetAgentTrace() const;
+
     virtual ~TraceDataSink();
 
    private:
+    std::map<std::string, std::string> additional_tracing_agent_trace_;
     MetadataFilterPredicate metadata_filter_predicate_;
     base::DictionaryValue metadata_;
   };
 
   // An implementation of this interface is passed when constructing a
   // TraceDataSink, and receives chunks of the final trace data as it's being
   // constructed.
   // Methods may be called from any thread.
   class CONTENT_EXPORT TraceDataEndpoint
       : public base::RefCountedThreadSafe<TraceDataEndpoint> {
@@ skipping 157 matching lines @@
   // Check if the tracing system is tracing
   virtual bool IsTracing() const = 0;
 
  protected:
   virtual ~TracingController() {}
 };
 
 }  // namespace content
 
 #endif  // CONTENT_PUBLIC_BROWSER_TRACING_CONTROLLER_H_