Use valid values

Author: schmidt-sebastian

firestore/src/main/field_value_main.cc

@@ -29,6 +29,12 @@ using Type = FieldValue::Type;
 
 // Constructors
 
+FieldValueInternal::FieldValueInternal() {
+  auto& value = absl::get<SharedMessage<google_firestore_v1_Value>>(value_);
+  value->which_value_type = google_firestore_v1_Value_map_value_tag;
+  value->map_value = {};
+}
+
 FieldValueInternal::FieldValueInternal(bool value) : type_{Type::kBoolean} {
   auto& proto = GetProtoValue();
   proto->which_value_type = google_firestore_v1_Value_boolean_value_tag;

firestore/src/main/field_value_main.h

@@ -27,7 +27,7 @@ namespace firestore {
 
 class FieldValueInternal {
  public:
-  FieldValueInternal() = default;
+  FieldValueInternal();
 
   explicit FieldValueInternal(bool value);
   explicit FieldValueInternal(int64_t value);