binding: Supports V8PrivateProperty::getOrUndefined.

third_party/WebKit/Source/bindings/core/v8/V8PrivateProperty.h

Index: third_party/WebKit/Source/bindings/core/v8/V8PrivateProperty.h
diff --git a/third_party/WebKit/Source/bindings/core/v8/V8PrivateProperty.h b/third_party/WebKit/Source/bindings/core/v8/V8PrivateProperty.h
index 8d7269577dce7423779dd0294673b1bdfeca9ddb..2a7349b8bf60c0b09baeaf4059f459e000801e86 100644
--- a/third_party/WebKit/Source/bindings/core/v8/V8PrivateProperty.h
+++ b/third_party/WebKit/Source/bindings/core/v8/V8PrivateProperty.h
@@ -72,6 +72,13 @@ public:
             return v8CallBoolean(object->HasPrivate(context, m_privateSymbol));
         }
 
+        // Returns the value of the private property if set, or undefined.
+        v8::Local<v8::Value> getOrUndefined(v8::Local<v8::Context> context, v8::Local<v8::Object> object) const
+        {
+            return v8CallOrCrash(object->GetPrivate(context, m_privateSymbol));
+        }
+
+        // Returns the value of the private property if set, or an empty handle.
         v8::Local<v8::Value> get(v8::Local<v8::Context> context, v8::Local<v8::Object> object) const
         {
             if (!v8CallBoolean(object->HasPrivate(context, m_privateSymbol)))