bindings: Adds ASSERTs to check the creation context passed to public APIs.

Source/web/WebDOMError.cpp

 /*
  * Copyright (C) 2013 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 49 matching lines @@
     return m_private->name();
 }
 
 WebString WebDOMError::message() const
 {
     if (!m_private.get())
         return WebString();
     return m_private->message();
 }
 
-v8::Local<v8::Value>  WebDOMError::toV8Value(v8::Local<v8::Object> /* creationContext */, v8::Isolate* isolate)
+v8::Local<v8::Value>  WebDOMError::toV8Value(v8::Local<v8::Object> creationContext, v8::Isolate* isolate)
 {
     // We no longer use |creationContext| because it's often misused and points
     // to a context faked by user script.
+    ASSERT(creationContext->CreationContext() == isolate->GetCurrentContext());
     if (!m_private.get())
         return v8::Local<v8::Value>();
     return toV8(m_private.get(), isolate->GetCurrentContext()->Global(), isolate);
 }
 
 WebDOMError::WebDOMError(DOMError* error)
     : m_private(error)
 {
 }
 
 WebDOMError& WebDOMError::operator=(DOMError* error)
 {
     m_private = error;
     return *this;
 }
 
 } // namespace blink