Switch base::Value typemapping to be by value instead of by unique_ptr.

chrome/utility/profile_import_handler.cc

Index: chrome/utility/profile_import_handler.cc
diff --git a/chrome/utility/profile_import_handler.cc b/chrome/utility/profile_import_handler.cc
index 0f6ea557c5081e28c7fbc0c3872a5c34a715edc7..e720434f44ac0f1c94c6b1ba5a4ddbd0d5bb3ba6 100644
--- a/chrome/utility/profile_import_handler.cc
+++ b/chrome/utility/profile_import_handler.cc
@@ -34,7 +34,7 @@ void ProfileImportHandler::Create(
 void ProfileImportHandler::StartImport(
     const importer::SourceProfile& source_profile,
     uint16_t items,
-    std::unique_ptr<base::DictionaryValue> localized_strings,
+    const base::DictionaryValue& localized_strings,
     chrome::mojom::ProfileImportObserverPtr observer) {
   content::UtilityThread::Get()->EnsureBlinkInitialized();
   importer_ = importer::CreateImporterByType(source_profile.importer_type);
@@ -55,7 +55,7 @@ void ProfileImportHandler::StartImport(
     ImporterCleanup();
   }
   bridge_ = new ExternalProcessImporterBridge(
-      *localized_strings,
+      localized_strings,
       ThreadSafeProfileImportObserverPtr::Create(std::move(observer)));
   import_thread_->task_runner()->PostTask(
       FROM_HERE, base::Bind(&Importer::StartImport, importer_,