Revert of base: Remove using:: declaration from version.h header.

components/variations/study_filtering_unittest.cc

 // Copyright 2014 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 "components/variations/study_filtering.h"
 
 #include <vector>
 
 #include "base/strings/string_split.h"
 #include "components/variations/processed_study.h"
@@ skipping 257 matching lines @@
     { "1.*", "2.3.4", false },
   };
 
   Study_Filter filter;
 
   // Min/max version not set should result in true.
   EXPECT_TRUE(internal::CheckStudyVersion(filter, base::Version("1.2.3")));
 
   for (size_t i = 0; i < arraysize(min_test_cases); ++i) {
     filter.set_min_version(min_test_cases[i].min_version);
-    const bool result = internal::CheckStudyVersion(
-        filter, base::Version(min_test_cases[i].version));
+    const bool result =
+        internal::CheckStudyVersion(filter, Version(min_test_cases[i].version));
     EXPECT_EQ(min_test_cases[i].expected_result, result) <<
         "Min. version case " << i << " failed!";
   }
   filter.clear_min_version();
 
   for (size_t i = 0; i < arraysize(max_test_cases); ++i) {
     filter.set_max_version(max_test_cases[i].max_version);
-    const bool result = internal::CheckStudyVersion(
-        filter, base::Version(max_test_cases[i].version));
+    const bool result =
+        internal::CheckStudyVersion(filter, Version(max_test_cases[i].version));
     EXPECT_EQ(max_test_cases[i].expected_result, result) <<
         "Max version case " << i << " failed!";
   }
 
   // Check intersection semantics.
   for (size_t i = 0; i < arraysize(min_test_cases); ++i) {
     for (size_t j = 0; j < arraysize(max_test_cases); ++j) {
       filter.set_min_version(min_test_cases[i].min_version);
       filter.set_max_version(max_test_cases[j].max_version);
 
       if (!min_test_cases[i].expected_result) {
-        const bool result = internal::CheckStudyVersion(
-            filter, base::Version(min_test_cases[i].version));
+        const bool result =
+            internal::CheckStudyVersion(
+                filter, Version(min_test_cases[i].version));
         EXPECT_FALSE(result) << "Case " << i << "," << j << " failed!";
       }
 
       if (!max_test_cases[j].expected_result) {
-        const bool result = internal::CheckStudyVersion(
-            filter, base::Version(max_test_cases[j].version));
+        const bool result =
+            internal::CheckStudyVersion(
+                filter, Version(max_test_cases[j].version));
         EXPECT_FALSE(result) << "Case " << i << "," << j << " failed!";
       }
     }
   }
 }
 
 TEST(VariationsStudyFilteringTest, CheckStudyHardwareClass) {
   struct {
     const char* hardware_class;
     const char* exclude_hardware_class;
@@ skipping 248 matching lines @@
 
   default_group->set_name("def");
   EXPECT_TRUE(processed_study.Init(&study, false));
   Study_Experiment* repeated_group = study.add_experiment();
   repeated_group->set_name("abc");
   repeated_group->set_probability_weight(1);
   EXPECT_FALSE(processed_study.Init(&study, false));
 }
 
 }  // namespace variations