Reorganize histograms for persistence.

base/metrics/metrics_hashes.h

Index: base/metrics/metrics_hashes.h
diff --git a/components/metrics/metrics_hashes.h b/base/metrics/metrics_hashes.h
similarity index 63%
rename from components/metrics/metrics_hashes.h
rename to base/metrics/metrics_hashes.h
index 0906c0aafaebbb567044e41c012526346b556959..92c4078f0a247d1dab81232774e4de1256a616d3 100644
--- a/components/metrics/metrics_hashes.h
+++ b/base/metrics/metrics_hashes.h
@@ -2,19 +2,20 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-#ifndef COMPONENTS_METRICS_METRICS_HASHES_H_
-#define COMPONENTS_METRICS_METRICS_HASHES_H_
+#ifndef BASE_METRICS_METRICS_HASHES_H_
+#define BASE_METRICS_METRICS_HASHES_H_
 
 #include <string>
 
+#include "base/base_export.h"
 #include "base/basictypes.h"
 
 namespace metrics {
 
 // Computes a uint64 hash of a given string based on its MD5 hash. Suitable for
 // metric names.
-uint64 HashMetricName(const std::string& name);
+BASE_EXPORT uint64 HashMetricName(const std::string& name);
 
 }  // namespace metrics
 
-#endif  // COMPONENTS_METRICS_METRICS_HASHES_H_
+#endif  // BASE_METRICS_METRICS_HASHES_H_