Move uniformity trials to its own file.

chrome/common/metrics/variations/uniformity_field_trials.h

+// Copyright (c) 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 CHROME_COMMON_METRICS_VARIATIONS_UNIFORMITY_FIELD_TRIALS_H_
+#define CHROME_COMMON_METRICS_VARIATIONS_UNIFORMITY_FIELD_TRIALS_H_
+
+#include "base/time.h"
+
+namespace chrome_variations {
+
+// A collection of one-time-randomized and session-randomized field trials
+// intended to test the uniformity and correctness of the field trial control,
+// bucketing and reporting systems.
+void SetupUniformityFieldTrials(const base::Time& install_date);
+
+}  // namespace chrome_variations
+
+#endif  // CHROME_COMMON_METRICS_VARIATIONS_UNIFORMITY_FIELD_TRIALS_H_