Change uses of base::JoinString to pass StringPieces where possible.

components/spellcheck/renderer/spellcheck_multilingual_unittest.cc

 // Copyright 2015 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 <stddef.h>
 
 #include <algorithm>
 #include <memory>
 #include <utility>
 
 #include "base/macros.h"
 #include "base/path_service.h"
+#include "base/strings/string_piece.h"
 #include "base/strings/string_split.h"
 #include "base/strings/string_util.h"
 #include "base/strings/utf_string_conversions.h"
 #include "components/spellcheck/common/spellcheck_common.h"
 #include "components/spellcheck/common/spellcheck_result.h"
 #include "components/spellcheck/renderer/spellcheck.h"
 #include "components/spellcheck/renderer/spellcheck_provider_test.h"
 #include "testing/gtest/include/gtest/gtest.h"
 #include "third_party/WebKit/public/platform/WebString.h"
 #include "third_party/WebKit/public/platform/WebVector.h"
@@ skipping 107 matching lines @@
       // A misspelled Greek word.
       {L"rocket destruyan \x0432\x0441\x0435\x0445 \x03B1\x03B1\x03B1\x03B1",
        22, 4},
       // An English word, then Russian, and then a misspelled English word.
       {L"rocket \x0432\x0441\x0435\x0445 rocktt", 12, 6},
   };
 
   // A sorted list of languages. This must start sorted to get all possible
   // permutations.
   std::string languages = "el-GR,en-US,es-ES,ru-RU";
-  std::vector<std::string> permuted_languages = base::SplitString(
+  std::vector<base::StringPiece> permuted_languages = base::SplitStringPiece(
       languages, ",", base::TRIM_WHITESPACE, base::SPLIT_WANT_ALL);
 
   do {
-    languages = base::JoinString(permuted_languages, ",");
-    ExpectSpellCheckWordResults(languages, kTestCases, arraysize(kTestCases));
+    std::string reordered_languages = base::JoinString(permuted_languages, ",");
+    ExpectSpellCheckWordResults(reordered_languages, kTestCases,
+                                arraysize(kTestCases));
   } while (std::next_permutation(permuted_languages.begin(),
                                  permuted_languages.end()));
 }
 
 TEST_F(MultilingualSpellCheckTest, MultilingualSpellCheckWordEnglishSpanish) {
   static const SpellcheckTestCase kTestCases[] = {
       {L"", 0, 0},
       {L"head hand foot legs arms", 0, 0},
       {L"head hand foot legs arms zzzz", 25, 4},
       {L"head hand zzzz foot legs arms", 10, 4},
@@ skipping 93 matching lines @@
         base::WideToUTF16(kTestCases[i].expected_suggestions),
         base::string16(1, ','), base::TRIM_WHITESPACE, base::SPLIT_WANT_ALL);
 
     EXPECT_EQ(expected_suggestions.size(), suggestions.size());
     for (size_t j = 0;
          j < std::min(expected_suggestions.size(), suggestions.size()); j++) {
       EXPECT_EQ(expected_suggestions[j], suggestions[j].utf16());
     }
   }
 }