Make File::Duplicate() const

base/files/file_tracing.h

 // Copyright 2015 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 BASE_FILES_FILE_TRACING_H_
 #define BASE_FILES_FILE_TRACING_H_
 
 #include <stdint.h>
 
 #include "base/base_export.h"
@@ skipping 19 matching lines @@
   static bool IsCategoryEnabled();
 
   class Provider {
    public:
     virtual ~Provider() = default;
 
     // Whether the file tracing category is currently enabled.
     virtual bool FileTracingCategoryIsEnabled() const = 0;
 
     // Enables file tracing for |id|. Must be called before recording events.
-    virtual void FileTracingEnable(void* id) = 0;
+    virtual void FileTracingEnable(const void* id) = 0;
 
     // Disables file tracing for |id|.
-    virtual void FileTracingDisable(void* id) = 0;
+    virtual void FileTracingDisable(const void* id) = 0;
 
     // Begins an event for |id| with |name|. |path| tells where in the directory
     // structure the event is happening (and may be blank). |size| is the number
     // of bytes involved in the event.
     virtual void FileTracingEventBegin(const char* name,
-                                       void* id,
+                                       const void* id,
                                        const FilePath& path,
                                        int64_t size) = 0;
 
     // Ends an event for |id| with |name|.
-    virtual void FileTracingEventEnd(const char* name, void* id) = 0;
+    virtual void FileTracingEventEnd(const char* name, const void* id) = 0;
   };
 
   // Sets a global file tracing provider to query categories and record events.
   static void SetProvider(Provider* provider);
 
   // Enables file tracing while in scope.
   class ScopedEnabler {
    public:
     ScopedEnabler();
     ~ScopedEnabler();
   };
 
   class ScopedTrace {
    public:
     ScopedTrace();
     ~ScopedTrace();
 
     // Called only if the tracing category is enabled. |name| is the name of the
     // event to trace (e.g. "Read", "Write") and must have an application
     // lifetime (e.g. static or literal). |file| is the file being traced; must
     // outlive this class. |size| is the size (in bytes) of this event.
-    void Initialize(const char* name, File* file, int64_t size);
+    void Initialize(const char* name, const File* file, int64_t size);
 
    private:
     // The ID of this trace. Based on the |file| passed to |Initialize()|. Must
     // outlive this class.
-    void* id_;
+    const void* id_;
 
     // The name of the event to trace (e.g. "Read", "Write"). Prefixed with
     // "File".
     const char* name_;
 
     DISALLOW_COPY_AND_ASSIGN(ScopedTrace);
   };
 
   DISALLOW_COPY_AND_ASSIGN(FileTracing);
 };
 
 }  // namespace base
 
 #endif  // BASE_FILES_FILE_TRACING_H_