Make File::Duplicate const

BUG=

Review-Url: https://codereview.chromium.org/2163063002
Cr-Commit-Position: refs/heads/master@{#406665}

base/files/file.h

@@ -290,7 +290,7 @@ class BASE_EXPORT File {
   // object that was created or initialized with this flag will have unlinked
   // the underlying file when it was created or opened. On Windows, the
   // underlying file is deleted when the last handle to it is closed.
-  File Duplicate();
+  File Duplicate() const;
 
   bool async() const { return async_; }
 

base/files/file_posix.cc

@@ -370,7 +370,7 @@ File::Error File::Unlock() {
   return CallFcntlFlock(file_.get(), false);
 }
 
-File File::Duplicate() {
+File File::Duplicate() const {
   if (!IsValid())
     return File();
 

base/files/file_tracing.cc

@@ -55,7 +55,7 @@ FileTracing::ScopedTrace::~ScopedTrace() {
 }
 
 void FileTracing::ScopedTrace::Initialize(const char* name,
-                                          File* file,
+                                          const File* file,
                                           int64_t size) {
   id_ = &file->trace_enabler_;
   name_ = name;

base/files/file_tracing.h

@@ -37,21 +37,21 @@ class BASE_EXPORT FileTracing {
     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.
@@ -73,12 +73,12 @@ class BASE_EXPORT FileTracing {
     // 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".

base/files/file_win.cc

@@ -249,7 +249,7 @@ File::Error File::Unlock() {
   return FILE_OK;
 }
 
-File File::Duplicate() {
+File File::Duplicate() const {
   if (!IsValid())
     return File();
 

content/browser/tracing/file_tracing_provider_impl.cc

@@ -20,23 +20,26 @@ bool FileTracingProviderImpl::FileTracingCategoryIsEnabled() const {
   return enabled;
 }
 
-void FileTracingProviderImpl::FileTracingEnable(void* id) {
+void FileTracingProviderImpl::FileTracingEnable(const void* id) {
   TRACE_EVENT_NESTABLE_ASYNC_BEGIN0(
       kFileTracingEventCategoryGroup, FILE_TRACING_PREFIX, id);
 }
 
-void FileTracingProviderImpl::FileTracingDisable(void* id) {
+void FileTracingProviderImpl::FileTracingDisable(const void* id) {
   TRACE_EVENT_NESTABLE_ASYNC_END0(
       kFileTracingEventCategoryGroup, FILE_TRACING_PREFIX, id);
 }
 
-void FileTracingProviderImpl::FileTracingEventBegin(
-    const char* name, void* id, const base::FilePath& path, int64_t size) {
+void FileTracingProviderImpl::FileTracingEventBegin(const char* name,
+                                                    const void* id,
+                                                    const base::FilePath& path,
+                                                    int64_t size) {
   TRACE_EVENT_NESTABLE_ASYNC_BEGIN2(kFileTracingEventCategoryGroup, name, id,
       "path", path.AsUTF8Unsafe(), "size", size);
 }
 
-void FileTracingProviderImpl::FileTracingEventEnd(const char* name, void* id) {
+void FileTracingProviderImpl::FileTracingEventEnd(const char* name,
+                                                  const void* id) {
   TRACE_EVENT_NESTABLE_ASYNC_END0(kFileTracingEventCategoryGroup, name, id);
 }
 

content/browser/tracing/file_tracing_provider_impl.h

@@ -21,11 +21,13 @@ class FileTracingProviderImpl : public base::FileTracing::Provider {
 
   // base::FileTracing::Provider:
   bool FileTracingCategoryIsEnabled() const override;
-  void FileTracingEnable(void* id) override;
-  void FileTracingDisable(void* id) override;
-  void FileTracingEventBegin(const char* name, void* id,
-                             const base::FilePath& path, int64_t size) override;
-  void FileTracingEventEnd(const char* name, void* id) override;
+  void FileTracingEnable(const void* id) override;
+  void FileTracingDisable(const void* id) override;
+  void FileTracingEventBegin(const char* name,
+                             const void* id,
+                             const base::FilePath& path,
+                             int64_t size) override;
+  void FileTracingEventEnd(const char* name, const void* id) override;
 
  private:
   DISALLOW_COPY_AND_ASSIGN(FileTracingProviderImpl);