Add ScriptValue.v8ValueUnsafe() to access the V8 value without cross-context access check.

Source/bindings/core/v8/ScriptValue.cpp

Index: Source/bindings/core/v8/ScriptValue.cpp
diff --git a/Source/bindings/core/v8/ScriptValue.cpp b/Source/bindings/core/v8/ScriptValue.cpp
index 0cd41264f7b328cf172de447c39de0ab3b537ec2..5a44d19317c1793a77a8a8df5ab1e736e52c97ed 100644
--- a/Source/bindings/core/v8/ScriptValue.cpp
+++ b/Source/bindings/core/v8/ScriptValue.cpp
@@ -58,6 +58,13 @@ v8::Handle<v8::Value> ScriptValue::v8Value() const
     return m_value->newLocal(isolate());
 }
 
+v8::Handle<v8::Value> ScriptValue::v8ValueUnsafe() const
+{
+    if (isEmpty())
+        return v8::Handle<v8::Value>();
+    return m_value->newLocal(isolate());
+}
+
 bool ScriptValue::toString(String& result) const
 {
     if (isEmpty())