components: Cleanup class/struct fwd declarations

components/feedback/tracing_manager.h

 // Copyright 2014 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 COMPONENTS_FEEDBACK_TRACING_MANAGER_H_
 #define COMPONENTS_FEEDBACK_TRACING_MANAGER_H_
 
 #include <map>
 #include <memory>
 #include <string>
 
 #include "base/callback.h"
 #include "base/macros.h"
 #include "base/memory/weak_ptr.h"
 #include "base/values.h"
 
 namespace base {
 
 class RefCountedString;
-class FilePath;
 
 }
 // Callback used for getting the output of a trace.
 typedef base::Callback<void(scoped_refptr<base::RefCountedString> trace_data)>
     TraceDataCallback;
 
 // This class is used to manage performance metrics that can be attached to
 // feedback reports.  This class is a Singleton that is owned by the preference
 // system.  It should only be created when it is enabled, and should only be
 // accessed elsewhere via Get().
@@ skipping 41 matching lines @@
   // Callback for the current trace request.
   TraceDataCallback trace_callback_;
 
   base::WeakPtrFactory<TracingManager> weak_ptr_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(TracingManager);
 };
 
 #endif  // COMPONENTS_FEEDBACK_TRACING_MANAGER_H_