Make lifetime in FunctionCallback signature more restrictive (#822)

This makes the callbacks themselves less restrictive. A test is added
the would fail to compile before.

src/function.rs

@@ -273,9 +273,10 @@ impl<'s> PropertyCallbackArguments<'s> {
 
 pub type FunctionCallback = extern "C" fn(*const FunctionCallbackInfo);
 
-impl<F> MapFnFrom<F> for FunctionCallback
+impl<'a, F> MapFnFrom<F> for FunctionCallback
 where
-  F: UnitType + Fn(&mut HandleScope, FunctionCallbackArguments, ReturnValue),
+  F: UnitType
+    + Fn(&mut HandleScope<'a>, FunctionCallbackArguments<'a>, ReturnValue),
 {
   fn mapping() -> Self {
     let f = |info: *const FunctionCallbackInfo| {

tests/test_api.rs

@@ -1901,6 +1901,21 @@ fn data_is_true_callback(
   assert!(data.is_true());
 }
 
+fn nested_builder<'a>(
+  scope: &mut v8::HandleScope<'a>,
+  args: v8::FunctionCallbackArguments<'a>,
+  _: v8::ReturnValue,
+) {
+  let arg0 = args.get(0);
+  v8::Function::builder(
+    |_: &mut v8::HandleScope,
+     _: v8::FunctionCallbackArguments,
+     _: v8::ReturnValue| {},
+  )
+  .data(arg0)
+  .build(scope);
+}
+
 #[test]
 fn function() {
   let _setup_guard = setup();
@@ -1913,6 +1928,9 @@ fn function() {
     let global = context.global(scope);
     let recv: v8::Local<v8::Value> = global.into();
 
+    // Just check that this compiles.
+    v8::Function::builder(nested_builder);
+
     // create function using template
     let fn_template = v8::FunctionTemplate::new(scope, fn_callback);
     let function = fn_template