[UMA] Use proper C++ objects to serialize tracked_objects across process boundaries.

chrome/browser/task_profiler/task_profiler_data_serializer.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 CHROME_BROWSER_TASK_PROFILER_TASK_PROFILER_DATA_SERIALIZER_H_
 #define CHROME_BROWSER_TASK_PROFILER_TASK_PROFILER_DATA_SERIALIZER_H_
 #pragma once
 
+#include "base/basictypes.h"
+#include "content/public/common/process_type.h"
+
 class FilePath;
 
+namespace base {
+class DictionaryValue;
+}
+
+namespace tracked_objects {
+struct SerializedProcessData;
+}
+
 namespace task_profiler {
 
 // This class collects task profiler data and serializes it to a file.  The file
 // format is compatible with the about:profiler UI.
 class TaskProfilerDataSerializer {
  public:
-  bool WriteToFile(const FilePath &path);
+  TaskProfilerDataSerializer() {}
+
+  // Re-serializes |process_data| and |process_type| into |dictionary|.
+  static void SerializeToJson(
+      const tracked_objects::SerializedProcessData& process_data,

[jar (doing other things), 2012/03/21 18:19:55]

IMO, this should be a method on the SerializedProcessData class.

I also suspect that the type should be embedded in that class.

[Ilya Sherman, 2012/03/21 19:23:02]

I'd strongly prefer to keep the JSON serialization code under chrome/browser/,
as there's no need for the base/ code to know how to serialize this data to JSON
-- the only client of it is a Chrome feature.  In theory, JSON serialization
could be useful for other projects building off of base/; but in practice, I'm
concerned that the JSON format is too closely tied to the chrome://profiler
page's JavaScript for this to work out smoothly.

+      content::ProcessType process_type,
+      base::DictionaryValue* dictionary);
+
+  bool WriteToFile(const FilePath& path);
+
+ private:
+  DISALLOW_COPY_AND_ASSIGN(TaskProfilerDataSerializer);
 };
 
 }  // namespace task_profiler
 
 #endif  // CHROME_BROWSER_TASK_PROFILER_TASK_PROFILER_DATA_SERIALIZER_H_