Remove all support for <applet> handling in Chrome.

blink-dev intent to remove thread:
https://groups.google.com/a/chromium.org/forum/#!msg/blink-dev/E9LKKtcKbv8/cB7QmTlACgAJ

BUG=470301

Review URL: https://codereview.chromium.org/1291723004

git-svn-id: svn://svn.chromium.org/blink/trunk@201659 bbb929c8-8fbe-4397-9dbb-9b2b20218538
194 files changed