Create variations target that depends on base.

components/variations/metrics_util.h

Index: components/variations/metrics_util.h
===================================================================
--- components/variations/metrics_util.h	(revision 0)
+++ components/variations/metrics_util.h	(working copy)
@@ -0,0 +1,20 @@
+// Copyright 2013 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 COMPONENTS_VARIATIONS_METRICS_UTIL_H_
+#define COMPONENTS_VARIATIONS_METRICS_UTIL_H_
+
+#include <string>
+
+#include "base/basictypes.h"
+
+namespace metrics {
+
+// Computes a uint32 hash of a given string based on its SHA1 hash. Suitable for
+// uniquely identifying field trial names and group names.
+uint32 HashName(const std::string& name);
+
+}  // namespace metrics
+
+#endif  // COMPONENTS_VARIATIONS_METRICS_UTIL_H_