chrome: Cleanup class/struct forward declarations

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_
 
 #include "base/macros.h"
 #include "base/process/process_handle.h"
 #include "components/metrics/proto/profiler_event.pb.h"
 
 namespace base {
 class DictionaryValue;
-class FilePath;
 }
 
 namespace tracked_objects {
 struct ProcessDataPhaseSnapshot;
 }
 
 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:
   TaskProfilerDataSerializer() {}
 
   // Writes the contents of |process_data_phase|, |process_id| and
   // |process_type| into |dictionary|.
   static void ToValue(
       const tracked_objects::ProcessDataPhaseSnapshot& process_data_phase,
       base::ProcessId process_id,
       metrics::ProfilerEventProto::TrackedObject::ProcessType process_type,
       base::DictionaryValue* dictionary);
 
  private:
   DISALLOW_COPY_AND_ASSIGN(TaskProfilerDataSerializer);
 };
 
 }  // namespace task_profiler
 
 #endif  // CHROME_BROWSER_TASK_PROFILER_TASK_PROFILER_DATA_SERIALIZER_H_