Revert 235213 "android: forwader2: Simplify Forwarder implementa..."

> android: forwader2: Simplify Forwarder implementation.
> 
> This patch does several things to the Forwarder class used in the 'forwarder2'
> tool:
> 
> - Add a Stop() method to gently ask the forwarder to shut-down. This stops
>   the forwarder from listening from incoming data, but keeps it running
>   until it could flush its buffer properly, to avoid packet loss.
> 
> - Simplify / refactor the buffer management code inside a Forwarder
>   instance, to make the state of its buffer, and their transitions,
>   more explict.
> 
> BUG=313809
> R=pliard@chromium.org
> 
> Review URL: https://codereview.chromium.org/61793013

TBR=digit@chromium.org

Review URL: https://codereview.chromium.org/70193013

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@235729 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 235729