Stop using WebCore namespace in generated code

This CL updates the templates we use for generated code to use |blink| rather
than |WebCore|. I've also updated a number comments and such that weren't
caught by my Python renaming script.

TBR=eseidel@chromium.org

Review URL: https://codereview.chromium.org/424983002

git-svn-id: svn://svn.chromium.org/blink/trunk@179114 bbb929c8-8fbe-4397-9dbb-9b2b20218538