ScriptPromise should check the constructor paraemter.

Source/bindings/v8/ScriptPromise.cpp

Index: Source/bindings/v8/ScriptPromise.cpp
diff --git a/Source/bindings/v8/ScriptPromise.cpp b/Source/bindings/v8/ScriptPromise.cpp
index c389c2aea94341b3c304139e24e8e2b5386eb329..812ecb4106d78b7ecf60daa1b6683b370431343b 100644
--- a/Source/bindings/v8/ScriptPromise.cpp
+++ b/Source/bindings/v8/ScriptPromise.cpp
@@ -39,6 +39,16 @@
 
 namespace WebCore {
 
+ScriptPromise::ScriptPromise(v8::Handle<v8::Value> value, v8::Isolate* isolate)
+{
+    if (value.IsEmpty() || !V8PromiseCustom::isPromise(value, isolate)) {
+        m_promise = ScriptValue(v8::Handle<v8::Value>(), isolate);
+        V8ThrowException::throwTypeError("the given value is not a Promise", isolate);
+        return;
+    }
+    m_promise = ScriptValue(value, isolate);
+}
+
 ScriptPromise ScriptPromise::then(PassOwnPtr<ScriptFunction> onFulfilled, PassOwnPtr<ScriptFunction> onRejected)
 {
     if (m_promise.hasNoValue() || !m_promise.isObject())
@@ -47,17 +57,16 @@ ScriptPromise ScriptPromise::then(PassOwnPtr<ScriptFunction> onFulfilled, PassOw
     return ScriptPromise(V8PromiseCustom::then(promise, adoptByGarbageCollector(onFulfilled), adoptByGarbageCollector(onRejected), isolate()), isolate());
 }
 
-ScriptPromise::ScriptPromise(const ScriptValue& value)
+ScriptPromise ScriptPromise::cast(const ScriptValue& value)

[kinuko, 2014/02/26 07:53:21]

nit: can we match the order in .h and in .cpp? (though this diff is easier to
read)

[yhirano, 2014/02/26 09:29:57]

Done.

 {
     if (value.hasNoValue())
-        return;
+        return ScriptPromise();
     v8::Local<v8::Value> v8Value(value.v8Value());
     v8::Isolate* isolate = value.isolate();
     if (V8PromiseCustom::isPromise(v8Value, isolate)) {
-        m_promise = value;
-        return;
+        return ScriptPromise(v8Value, isolate);
     }
-    m_promise = ScriptValue(V8PromiseCustom::toPromise(v8Value, isolate), isolate);
+    return ScriptPromise(V8PromiseCustom::toPromise(v8Value, isolate), isolate);
 }
 
 ScriptPromise ScriptPromise::createPending(ExecutionContext* context)