Revert 227722 "Introduce a new attribute to externally_connectable,"

> Introduce a new attribute to externally_connectable,
> accepts_tls_channel_id.  When sites are allowed to connect to an
> extension, and specify include_tls_channel_id in their
> chrome.runtime.connect or chrome.runtime.sendMessage options,
> and the extension sets the accepts_tls_channel_id attribute,
> automatically annotate the TLS channel ID as an attribute of the
> MessageSender given to the onConnectExternal handler.
> 
> BUG=259097
> 
> Review URL: https://codereview.chromium.org/23002007

TBR=juanlang@google.com

Review URL: https://codereview.chromium.org/26686002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@227723 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 227723