Convert //ios from scoped_ptr to std::unique_ptr.

ios/crnet/sdch_owner_pref_storage.cc

Index: ios/crnet/sdch_owner_pref_storage.cc
diff --git a/ios/crnet/sdch_owner_pref_storage.cc b/ios/crnet/sdch_owner_pref_storage.cc
index 3af81f5f7a681dae091cbabd4a0f0d548b1a7ee2..292eaa24f2ea0dd8503846826cde569df351102f 100644
--- a/ios/crnet/sdch_owner_pref_storage.cc
+++ b/ios/crnet/sdch_owner_pref_storage.cc
@@ -72,7 +72,8 @@ bool SdchOwnerPrefStorage::GetMutableValue(base::DictionaryValue** result) {
   return result_value->GetAsDictionary(result);
 }
 
-void SdchOwnerPrefStorage::SetValue(scoped_ptr<base::DictionaryValue> value) {
+void SdchOwnerPrefStorage::SetValue(
+    std::unique_ptr<base::DictionaryValue> value) {
   storage_->SetValue(storage_key_, std::move(value),
                      WriteablePrefStore::DEFAULT_PREF_WRITE_FLAGS);
 }