Fix accessing empty vector in V8FunctionInvoker

atom/common/native_mate_converters/callback.h

@@ -56,7 +56,8 @@ struct V8FunctionInvoker<v8::Local<v8::Value>(ArgTypes...)> {
     v8::Local<v8::Context> context = holder->CreationContext();
     v8::Context::Scope context_scope(context);
     std::vector<v8::Local<v8::Value>> args { ConvertToV8(isolate, raw)... };
-    v8::Local<v8::Value> ret(holder->Call(holder, args.size(), &args.front()));
+    v8::Local<v8::Value> ret(holder->Call(
+        holder, args.size(), args.empty() ? nullptr : &args.front()));
     return handle_scope.Escape(ret);
   }
 };
@@ -76,7 +77,8 @@ struct V8FunctionInvoker<void(ArgTypes...)> {
     v8::Local<v8::Context> context = holder->CreationContext();
     v8::Context::Scope context_scope(context);
     std::vector<v8::Local<v8::Value>> args { ConvertToV8(isolate, raw)... };
-    holder->Call(holder, args.size(), &args.front());
+    holder->Call(
+        holder, args.size(), args.empty() ? nullptr : &args.front());
   }
 };
 
@@ -97,8 +99,8 @@ struct V8FunctionInvoker<ReturnType(ArgTypes...)> {
     v8::Context::Scope context_scope(context);
     std::vector<v8::Local<v8::Value>> args { ConvertToV8(isolate, raw)... };
     v8::Local<v8::Value> result;
-    auto maybe_result =
-        holder->Call(context, holder, args.size(), &args.front());
+    auto maybe_result = holder->Call(
+        context, holder, args.size(), args.empty() ? nullptr : &args.front());
     if (maybe_result.ToLocal(&result))
       Converter<ReturnType>::FromV8(isolate, result, &ret);
     return ret;