Code health: remove deprecated Value::GetAsString in spellcheck_service_browsertest.cc

Bug: chromium:1187007
Change-Id: I2f8dfa395468a599f6efac757e630f25c25fdbac
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/3013536
Reviewed-by: Josh Simmons <jds@google.com>
Commit-Queue: Alex Rudenko <alexrudenko@chromium.org>
Cr-Commit-Position: refs/heads/master@{#899603}
diff --git a/chrome/browser/spellchecker/spellcheck_service_browsertest.cc b/chrome/browser/spellchecker/spellcheck_service_browsertest.cc
index d8a8e41..df449a2f0 100644
--- a/chrome/browser/spellchecker/spellcheck_service_browsertest.cc
+++ b/chrome/browser/spellchecker/spellcheck_service_browsertest.cc
@@ -170,9 +170,8 @@
         prefs_->GetList(spellcheck::prefs::kSpellCheckDictionaries);
     std::vector<base::StringPiece> dictionaries;
     for (const auto& item_value : list_value->GetList()) {
-      base::StringPiece dictionary;
-      EXPECT_TRUE(item_value.GetAsString(&dictionary));
-      dictionaries.push_back(dictionary);
+      EXPECT_TRUE(item_value.is_string());
+      dictionaries.push_back(item_value.GetString());
     }
     return base::JoinString(dictionaries, ",");
   }