bindings: Add empty checks for toV8()

Source/bindings/core/v8/V8Binding.cpp

Index: Source/bindings/core/v8/V8Binding.cpp
diff --git a/Source/bindings/core/v8/V8Binding.cpp b/Source/bindings/core/v8/V8Binding.cpp
index 2f82762487dbedee4781eded2d1fb74e789116d6..fca18951df66cf89cb4232539e4dcbe7c24fb658 100644
--- a/Source/bindings/core/v8/V8Binding.cpp
+++ b/Source/bindings/core/v8/V8Binding.cpp
@@ -101,6 +101,8 @@ PassRefPtrWillBeRawPtr<NodeFilter> toNodeFilter(v8::Handle<v8::Value> callback,
     RefPtrWillBeRawPtr<NodeFilter> filter = NodeFilter::create();
 
     v8::Handle<v8::Object> filterWrapper = toV8(filter.get(), creationContext, scriptState->isolate()).As<v8::Object>();
+    if (filterWrapper.IsEmpty())

[haraken, 2015/04/28 04:24:59]

This is a bit too late to check the emptiness. We need to check it before
calling .As.

[bashi, 2015/04/28 05:41:53]

Done.

+        return nullptr;
 
     RefPtrWillBeRawPtr<NodeFilterCondition> condition = V8NodeFilterCondition::create(callback, filterWrapper, scriptState);
     filter->setCondition(condition.release());