Make the event-handler handle backpreasure.

Make the event-handler handle backpreasure.

We now limit the number of active events per fd to 8.

BUG=
R=whesse@google.com

Committed: https://code.google.com/p/dart/source/detail?r=33649

[Anders Johnsen, 2014-03-13 09:41:18]

Note that this is mostly a revert of some of the latest changes, with the
addition of the `tokens`.

[Bill Hesse, 2014-03-13 11:48:01]

LGTM.

https://codereview.chromium.org/198743002/diff/60001/runtime/bin/eventhandler...
File runtime/bin/eventhandler_android.cc (left):

https://codereview.chromium.org/198743002/diff/60001/runtime/bin/eventhandler...
runtime/bin/eventhandler_android.cc:175: AddToEpollInstance(epoll_fd_, sd);
I assume there is no case in which the only message received will be a
ShutdownRead or ShutdownWrite, in which case this won't be called on a new
SocketData.

https://codereview.chromium.org/198743002/diff/60001/runtime/bin/eventhandler...
File runtime/bin/eventhandler_android.cc (right):

https://codereview.chromium.org/198743002/diff/60001/runtime/bin/eventhandler...
runtime/bin/eventhandler_android.cc:231: // Return only error if EPOLLIN is
present.
Return error only if

[Anders Johnsen, 2014-03-13 12:02:21]

https://codereview.chromium.org/198743002/diff/60001/runtime/bin/eventhandler...
File runtime/bin/eventhandler_android.cc (left):

https://codereview.chromium.org/198743002/diff/60001/runtime/bin/eventhandler...
runtime/bin/eventhandler_android.cc:175: AddToEpollInstance(epoll_fd_, sd);
On 2014/03/13 11:48:02, Bill Hesse wrote:
> I assume there is no case in which the only message received will be a
> ShutdownRead or ShutdownWrite, in which case this won't be called on a new
> SocketData.

No, that is fine. The only thing from 'sd' we use is the fd.

https://codereview.chromium.org/198743002/diff/60001/runtime/bin/eventhandler...
File runtime/bin/eventhandler_android.cc (right):

https://codereview.chromium.org/198743002/diff/60001/runtime/bin/eventhandler...
runtime/bin/eventhandler_android.cc:231: // Return only error if EPOLLIN is
present.
On 2014/03/13 11:48:02, Bill Hesse wrote:
> Return error only if

Done.

[Anders Johnsen, 2014-03-13 12:03:07]

Committed patchset #5 manually as r33649 (presubmit successful).

[Søren Gjesse, 2014-03-14 08:23:12]

lgtm