bindings: Add empty checks for toV8()

Source/core/dom/DOMDataView.cpp

Index: Source/core/dom/DOMDataView.cpp
diff --git a/Source/core/dom/DOMDataView.cpp b/Source/core/dom/DOMDataView.cpp
index 60d96f4cae5c5645d9190b36a6887aa03db9bd55..d19e2998157ca6db7811d6cf0db73e57618cd3a1 100644
--- a/Source/core/dom/DOMDataView.cpp
+++ b/Source/core/dom/DOMDataView.cpp
@@ -29,6 +29,8 @@ v8::Handle<v8::Object> DOMDataView::wrap(v8::Handle<v8::Object> creationContext,
 
     const WrapperTypeInfo* wrapperTypeInfo = this->wrapperTypeInfo();
     v8::Local<v8::Value> v8Buffer = toV8(buffer(), creationContext, isolate);
+    if (v8Buffer.IsEmpty())
+        return v8::Handle<v8::Object>();

[yurys, 2015/04/28 07:05:25]

AFAIU this is where v8::MaybeLocal should be used to declare that the operation
may fail and return value may be empty handle. Are you going to change the
return type to MaybeLocal later?

[bashi, 2015/04/28 07:09:45]

We use MaybeLocal if we can guarantee that the function fails iff an exception
is thrown. toV8() is not the case so I don't have a plan to change the API.

We may relax this restriction in the future, but that's my current thought.

     ASSERT(v8Buffer->IsArrayBuffer());
 
     v8::Handle<v8::Object> wrapper = v8::DataView::New(v8Buffer.As<v8::ArrayBuffer>(), byteOffset(), byteLength());