Create variations target that depends on base.

components/variations/entropy_provider.h

 // Copyright (c) 2012 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_ENTROPY_PROVIDER_H_
-#define CHROME_COMMON_METRICS_ENTROPY_PROVIDER_H_
+#ifndef COMPONENTS_VARIATIONS_ENTROPY_PROVIDER_H_
+#define COMPONENTS_VARIATIONS_ENTROPY_PROVIDER_H_
 
 #include <functional>
 #include <string>
 #include <vector>
 
 #include "base/basictypes.h"
 #include "base/compiler_specific.h"
 #include "base/metrics/field_trial.h"
 #include "third_party/mt19937ar/mt19937ar.h"
 
@@ skipping 67 matching lines @@
 
  private:
   uint16 low_entropy_source_;
   size_t low_entropy_source_max_;
 
   DISALLOW_COPY_AND_ASSIGN(PermutedEntropyProvider);
 };
 
 }  // namespace metrics
 
-#endif  // CHROME_COMMON_METRICS_ENTROPY_PROVIDER_H_
+#endif  // COMPONENTS_VARIATIONS_ENTROPY_PROVIDER_H_