There is a work around that may work. If you use the
vulcanize tool to inline all of the polymer elements, then there probably will not be any "Access Denied" errors.
After installing vulcanize (see the link above), you can run `vulcanize --inline index.html` and it will build a file called `vulcanized.html` that should have no external dependencies anymore.
However, this is just a workaround, and I cannot guarantee that it will work for you.
In general, running web applications from file:/// is not advisable due to security concerns, which is why all browser vendors have made it difficult.
I suggest that you find a way to alter your business requirements on this issue, or it will only become more problematic for you in the future.