V8 Bindings: Don't attempt to set an empty V8HiddenValue

third_party/WebKit/Source/bindings/core/v8/V8HiddenValue.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 "bindings/core/v8/V8HiddenValue.h"
 
 #include "bindings/core/v8/ScriptState.h"
 #include "bindings/core/v8/ScriptWrappable.h"
 #include "bindings/core/v8/V8Binding.h"
 
@@ skipping 19 matching lines @@
     // Callsites interpret an empty handle has absence of a result.
     if (!v8CallBoolean(object->HasPrivate(context, privateKey)))
         return v8::Local<v8::Value>();
     if (object->GetPrivate(context, privateKey).ToLocal(&value))
         return value;
     return v8::Local<v8::Value>();
 }
 
 bool V8HiddenValue::setHiddenValue(ScriptState* scriptState, v8::Local<v8::Object> object, v8::Local<v8::String> key, v8::Local<v8::Value> value)
 {
+    if (UNLIKELY(value.IsEmpty()))
+        return false;
     return v8CallBoolean(object->SetPrivate(scriptState->context(), v8::Private::ForApi(scriptState->isolate(), key), value));
 }
 
 bool V8HiddenValue::deleteHiddenValue(ScriptState* scriptState, v8::Local<v8::Object> object, v8::Local<v8::String> key)
 {
     // Actually deleting the value would make force the object into dictionary mode which is unnecessarily slow. Instead, we replace the hidden value with "undefined".
     return v8CallBoolean(object->SetPrivate(scriptState->context(), v8::Private::ForApi(scriptState->isolate(), key), v8::Undefined(scriptState->isolate())));
 }
 
 v8::Local<v8::Value> V8HiddenValue::getHiddenValueFromMainWorldWrapper(ScriptState* scriptState, ScriptWrappable* wrappable, v8::Local<v8::String> key)
 {
     v8::Local<v8::Object> wrapper = wrappable->newLocalWrapper(scriptState->isolate());
     return wrapper.IsEmpty() ? v8::Local<v8::Value>() : getHiddenValue(scriptState, wrapper, key);
 }
 
 } // namespace blink