Remove 'using base::string16;' from base/strings/string16.h and remove temporary

chrome/browser/autocomplete/history_url_provider_unittest.cc

Index: chrome/browser/autocomplete/history_url_provider_unittest.cc
diff --git a/chrome/browser/autocomplete/history_url_provider_unittest.cc b/chrome/browser/autocomplete/history_url_provider_unittest.cc
index a5f63b389032936c1e07c81eab565ea185d6072f..0188ed19085488a21f91608e171cb7b0574386c6 100644
--- a/chrome/browser/autocomplete/history_url_provider_unittest.cc
+++ b/chrome/browser/autocomplete/history_url_provider_unittest.cc
@@ -1006,7 +1006,7 @@ TEST_F(HistoryURLProviderTest, HUPScoringExperiment) {
     autocomplete_->scoring_params_.experimental_scoring_enabled = false;
     ASSERT_NO_FATAL_FAILURE(
         RunTest(ASCIIToUTF16(test_cases[i].input),
-                string16(), false, output, max_matches));
+                base::string16(), false, output, max_matches));
     for (int j = 0; j < max_matches; ++j) {
       EXPECT_EQ(test_cases[i].matches[j].control_relevance,
                 matches_[j].relevance);
@@ -1016,7 +1016,7 @@ TEST_F(HistoryURLProviderTest, HUPScoringExperiment) {
     autocomplete_->scoring_params_.experimental_scoring_enabled = true;
     ASSERT_NO_FATAL_FAILURE(
         RunTest(ASCIIToUTF16(test_cases[i].input),
-                string16(), false, output, max_matches));
+                base::string16(), false, output, max_matches));
     for (int j = 0; j < max_matches; ++j) {
       EXPECT_EQ(test_cases[i].matches[j].experiment_relevance,
                 matches_[j].relevance);