Added IsConstructorCall to gin::Arguments.

gin/wrappable_unittest.cc

Index: gin/wrappable_unittest.cc
diff --git a/gin/wrappable_unittest.cc b/gin/wrappable_unittest.cc
index 9843329906468655a65d31916eb8ae1bd0a9194d..f3de48fe09ae278e34d2302b3aedd94beb017b11 100644
--- a/gin/wrappable_unittest.cc
+++ b/gin/wrappable_unittest.cc
@@ -97,8 +97,11 @@ class MyCallableObject : public Wrappable<MyCallableObject> {
   virtual ~MyCallableObject() {
   }
 
-  void Call(int val) {
-    result_ = val;
+  void Call(int val, const gin::Arguments& arguments) {
+    if (arguments.IsConstructCall())
+      arguments.ThrowTypeError("Cannot be called as constructor.");
+    else
+      result_ = val;
   }
 
   int result_;
@@ -245,4 +248,26 @@ TEST_F(WrappableTest, CallAsFunction) {
   EXPECT_EQ(42, object->result());
 }
 
+TEST_F(WrappableTest, CallAsConstructor) {
+  v8::Isolate* isolate = instance_->isolate();
+  v8::HandleScope handle_scope(isolate);
+
+  gin::Handle<MyCallableObject> object(MyCallableObject::Create(isolate));
+  EXPECT_EQ(0, object->result());
+  v8::Handle<v8::String> source = StringToV8(isolate,
+                                             "(function(obj) {"
+                                             "new obj(42);"
+                                             "})");
+  gin::TryCatch try_catch;
+  v8::Handle<v8::Script> script = v8::Script::Compile(source);
+  v8::Handle<v8::Value> val = script->Run();
+  v8::Handle<v8::Function> func;
+  EXPECT_TRUE(ConvertFromV8(isolate, val, &func));
+  v8::Handle<v8::Value> argv[] = {
+    ConvertToV8(isolate, object.get())
+  };
+  func->Call(v8::Undefined(isolate), 1, argv);
+  EXPECT_TRUE(try_catch.HasCaught());
+}
+
 }  // namespace gin