Add granular file tracing.

content/browser/tracing/file_tracing_provider_impl.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 CONTENT_BROWSER_TRACING_FILE_TRACING_PROVIDER_IMPL_H_
+#define CONTENT_BROWSER_TRACING_FILE_TRACING_PROVIDER_IMPL_H_
+
+#include "base/files/file_tracing.h"
+#include "base/macros.h"
+
+namespace content {
+
+extern const char kFileTracingEventCategoryGroup[];
+
+class FileTracingProviderImpl : public base::FileTracing::Provider {
+ public:
+  FileTracingProviderImpl();
+  ~FileTracingProviderImpl();
+
+  // 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 size) override;
+  void FileTracingEventEnd(const char* name, void* id,
+                           const base::FilePath& path, int64 size) override;
+
+ private:
+  DISALLOW_COPY_AND_ASSIGN(FileTracingProviderImpl);
+};
+
+}  // namespace content
+
+#endif  // CONTENT_BROWSER_TRACING_FILE_TRACING_PROVIDER_IMPL_H_