Record UMA statistics for file_stream operations.

net/base/file_stream_metrics.h

+// Copyright (c) 2011 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.
+
+// File error statistics gathering.
+
+#ifndef NET_BASE_FILE_STREAM_METRICS_H_
+#define NET_BASE_FILE_STREAM_METRICS_H_
+#pragma once
+
+namespace net {
+
+enum FileErrorSource {
+  FILE_ERROR_SOURCE_OPEN = 0,
+  FILE_ERROR_SOURCE_WRITE,
+  FILE_ERROR_SOURCE_READ,
+  FILE_ERROR_SOURCE_SEEK,
+  FILE_ERROR_SOURCE_FLUSH,
+  FILE_ERROR_SOURCE_SET_EOF,
+  FILE_ERROR_SOURCE_GET_SIZE,
+  FILE_ERROR_SOURCE_COUNT,
+};
+
+// UMA error statistics gathering.
+// Put the error value into a bucket.
+int GetErrorBucket(int error);
+// The largest bucket number, plus 1.

[cbentzel, 2011/08/18 13:31:28]

Nit: there's usually a new-line between function declaration and the comment
afterwards.

[ahendrickson, 2011/08/18 15:56:45]

Done.

+int MaxBucket();
+// The highest error value we want to individually report.
+int MaxError();
+// |error| is a platform-specific error (Windows or Posix).
+// |source| indicates the operation that resulted in the error.
+// |record| is a flag indicating that we are interested in this error.
+void RecordFileError(int error, FileErrorSource source, bool record);
+
+}  // namespace net
+
+#endif  // NET_BASE_FILE_STREAM_METRICS_H_