bindings: Add empty checks for toV8()

Source/core/dom/DOMDataView.cpp

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "config.h"
 #include "core/dom/DOMDataView.h"
 
 #include "bindings/core/v8/DOMDataStore.h"
 #include "bindings/core/v8/V8ArrayBuffer.h"
 #include "bindings/core/v8/V8DOMWrapper.h"
@@ skipping 11 matching lines @@
 {
     // It's possible that no one except for the new wrapper owns this object at
     // this moment, so we have to prevent GC to collect this object until the
     // object gets associated with the wrapper.
     RefPtr<DOMDataView> protect(this);
 
     ASSERT(!DOMDataStore::containsWrapper(this, isolate));
 
     const WrapperTypeInfo* wrapperTypeInfo = this->wrapperTypeInfo();
     v8::Local<v8::Value> v8Buffer = toV8(buffer(), creationContext, isolate);
+    if (v8Buffer.IsEmpty())
+        return v8::Handle<v8::Object>();

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

Remove.

[Yuki, 2015/04/28 04:47:57]

I think it's good to check that v8Buffer is not v8::Object or anything else but
just v8::ArrayBuffer.  And this ASSERT doesn't affect the performance in release
mode, I'd prefer keeping this sort of checks.

     ASSERT(v8Buffer->IsArrayBuffer());
 
     v8::Handle<v8::Object> wrapper = v8::DataView::New(v8Buffer.As<v8::ArrayBuffer>(), byteOffset(), byteLength());
 
     return associateWithWrapper(isolate, wrapperTypeInfo, wrapper);
 }
 
 v8::Handle<v8::Object> DOMDataView::associateWithWrapper(v8::Isolate* isolate, const WrapperTypeInfo* wrapperTypeInfo, v8::Handle<v8::Object> wrapper)
 {
     return V8DOMWrapper::associateObjectWithWrapper(isolate, this, wrapperTypeInfo, wrapper);
 }
 
 } // namespace blink