[V8] Add v8::Value::TypeOf to API

There is TypeOf static method on object inside V8. In this CL I've extracted it via API.

LOG=Y
R=yangguo@chromium.org
BUG=chromium:595206

Review-Url: https://codereview.chromium.org/1829833002
Cr-Commit-Position: refs/heads/master@{#36113}

include/v8.h

@@ -2027,6 +2027,8 @@ class V8_EXPORT Value : public Data {
 
   template <class T> V8_INLINE static Value* Cast(T* value);
 
+  Local<String> TypeOf(v8::Isolate*);
+
  private:
   V8_INLINE bool QuickIsUndefined() const;
   V8_INLINE bool QuickIsNull() const;

src/api.cc

@@ -3549,6 +3549,12 @@ bool Value::SameValue(Local<Value> that) const {
   return self->SameValue(*other);
 }
 
+Local<String> Value::TypeOf(v8::Isolate* external_isolate) {
+  i::Isolate* isolate = reinterpret_cast<i::Isolate*>(external_isolate);
+  ENTER_V8(isolate);
+  LOG_API(isolate, "v8::Value::TypeOf()");
+  return Utils::ToLocal(i::Object::TypeOf(isolate, Utils::OpenHandle(this)));
+}
 
 Maybe<bool> v8::Object::Set(v8::Local<v8::Context> context,
                             v8::Local<Value> key, v8::Local<Value> value) {

test/cctest/test-api.cc

@@ -6391,6 +6391,46 @@ THREADED_TEST(Equality) {
   CHECK(!v8::False(isolate)->SameValue(v8::Undefined(isolate)));
 }
 
+THREADED_TEST(TypeOf) {
+  LocalContext context;
+  v8::Isolate* isolate = context->GetIsolate();
+  v8::HandleScope scope(context->GetIsolate());
+
+  Local<v8::FunctionTemplate> t1 = v8::FunctionTemplate::New(isolate);
+  Local<v8::Function> fun = t1->GetFunction(context.local()).ToLocalChecked();
+
+  CHECK(v8::Undefined(isolate)
+            ->TypeOf(isolate)
+            ->Equals(context.local(), v8_str("undefined"))
+            .FromJust());
+  CHECK(v8::Null(isolate)
+            ->TypeOf(isolate)
+            ->Equals(context.local(), v8_str("object"))
+            .FromJust());
+  CHECK(v8_str("str")
+            ->TypeOf(isolate)
+            ->Equals(context.local(), v8_str("string"))
+            .FromJust());
+  CHECK(v8_num(0.0)
+            ->TypeOf(isolate)
+            ->Equals(context.local(), v8_str("number"))
+            .FromJust());
+  CHECK(v8_num(1)
+            ->TypeOf(isolate)
+            ->Equals(context.local(), v8_str("number"))
+            .FromJust());
+  CHECK(v8::Object::New(isolate)
+            ->TypeOf(isolate)
+            ->Equals(context.local(), v8_str("object"))
+            .FromJust());
+  CHECK(v8::Boolean::New(isolate, true)
+            ->TypeOf(isolate)
+            ->Equals(context.local(), v8_str("boolean"))
+            .FromJust());
+  CHECK(fun->TypeOf(isolate)
+            ->Equals(context.local(), v8_str("function"))
+            .FromJust());
+}
 
 THREADED_TEST(MultiRun) {
   LocalContext context;