[Metrics] Move CachingPermutedEntropyProvider into the variations component.

chrome/common/metrics/caching_permuted_entropy_provider_unittest.cc

-// 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.
-
-#include "chrome/common/metrics/caching_permuted_entropy_provider.h"
-
-#include <string>
-
-#include "base/basictypes.h"
-#include "base/prefs/testing_pref_service.h"
-#include "testing/gtest/include/gtest/gtest.h"
-
-namespace metrics {
-
-// Size of the low entropy source to use for the permuted entropy provider
-// in tests.
-const size_t kMaxLowEntropySize = 8000;
-
-// Field trial names used in unit tests.
-const char* const kTestTrialNames[] = { "TestTrial", "AnotherTestTrial",
-                                        "NewTabButton" };
-
-TEST(CachingPermutedEntropyProviderTest, HasConsistentResults) {
-  TestingPrefServiceSimple prefs;
-  CachingPermutedEntropyProvider::RegisterPrefs(prefs.registry());
-  const int kEntropyValue = 1234;
-
-  // Check that the caching provider returns the same results as the non caching
-  // one. Loop over the trial names twice, to test that caching returns the
-  // expected results.
-  PermutedEntropyProvider provider(kEntropyValue, kMaxLowEntropySize);
-  for (size_t i = 0; i < 2 * arraysize(kTestTrialNames); ++i) {
-    CachingPermutedEntropyProvider cached_provider(&prefs, kEntropyValue,
-                                                   kMaxLowEntropySize);
-    const std::string trial_name =
-        kTestTrialNames[i % arraysize(kTestTrialNames)];
-    EXPECT_DOUBLE_EQ(provider.GetEntropyForTrial(trial_name, 0),
-                     cached_provider.GetEntropyForTrial(trial_name, 0));
-  }
-
-  // Now, do the same test re-using the same caching provider.
-  CachingPermutedEntropyProvider cached_provider(&prefs, kEntropyValue,
-                                                 kMaxLowEntropySize);
-  for (size_t i = 0; i < 2 * arraysize(kTestTrialNames); ++i) {
-    const std::string trial_name =
-        kTestTrialNames[i % arraysize(kTestTrialNames)];
-    EXPECT_DOUBLE_EQ(provider.GetEntropyForTrial(trial_name, 0),
-                     cached_provider.GetEntropyForTrial(trial_name, 0));
-  }
-}
-
-}  // namespace metrics