Generate V8HTMLElementWrapperFactory with Python

This CL replaces the hold Perl-based V8HTMLElementWrapperFactory with a Python
implementation based on jinja2 templates. After this CL, we are a few inches
from dropping name_names.pl for HTML.

R=eseidel@chromium.org

Review URL: https://codereview.chromium.org/27436003

git-svn-id: svn://svn.chromium.org/blink/trunk@159967 bbb929c8-8fbe-4397-9dbb-9b2b20218538