The upcoming rewrite of the browser plugin has colliding names for IPC messages.
Rename existing messages to Old in preparation for the new implementation.
BUG=none
Review URL: https://chromiumcodereview.appspot.com/10829074
git-svn-id: svn://svn.chromium.org/chrome/trunk/src@149116 0039d316-1c4b-4281-b951-d872f2087c98
