Integrate Crashpad UMA

base/metrics/persistent_metrics_file_util.h

Index: base/metrics/persistent_metrics_file_util.h
diff --git a/base/metrics/persistent_metrics_file_util.h b/base/metrics/persistent_metrics_file_util.h
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+// Copyright 2016 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_METRICS_PERSISTENT_METRICS_FILE_UTIL_H_
+#define BASE_METRICS_PERSISTENT_METRICS_FILE_UTIL_H_
+
+#include "base/base_export.h"
+
+namespace base {
+
+class FilePath;
+
+// Initializes a pair of metrics files in the given directory, using
+// |metrics_name| as the basename of the previous run file, and basename +
+// "-active" for the current run, with the given size. The basename one should
+// be associated with the previous run when registered with the metrics system,
+// and the "-active" with the current run.
+BASE_EXPORT void InitializeGlobalPersistentMetricsStorage(
+    const base::FilePath& dir,
+    const char* metrics_name,
+    size_t size);
+
+// If there is a global metrics file being updated on disk, mark it to be
+// deleted when the process exits. A normal shutdown is almost complete
+// so there is no benefit in keeping a file with no new data to be processed
+// during the next startup sequence. Deleting the file during shutdown adds
+// an extra disk-access or two to shutdown but eliminates the unnecessary
+// processing of the contents during startup only to find nothing.
+BASE_EXPORT void CleanUpGlobalPersistentHistogramStorage();
+
+}  // namespace base
+
+#endif  // BASE_METRICS_PERSISTENT_METRICS_FILE_UTIL_H_