ozone: evdev: Move read polling into EventConverterEvdev

ozone: evdev: Move read polling into EventConverterEvdev

All of the subclasses do the same thing for the polling part, so share
it. Not all of them use DispatchEventToCallback, so remove that part.

NOTRY=true

Committed: https://crrev.com/f04d0478359d667814c973ba11d6e8840e00b4be
Cr-Commit-Position: refs/heads/master@{#294446}

[spang, 2014-09-11 15:36:47]

spang@chromium.org changed reviewers:
+ kpschoedel@chromium.org

[kpschoedel, 2014-09-11 16:58:33]

lgtm

[spang, 2014-09-11 19:31:13]

The CQ bit was checked by spang@chromium.org

[commit-bot: I haz the power, 2014-09-11 19:33:43]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patchset/561243002/1

[commit-bot: I haz the power, 2014-09-11 19:53:17]

Committed patchset #1 (id:1) as 7d26847854ad8f8814515850d91b51226b8557ba

[commit-bot: I haz the power, 2014-09-11 20:02:38]

Patchset 1 (id:??) landed as
https://crrev.com/f04d0478359d667814c973ba11d6e8840e00b4be
Cr-Commit-Position: refs/heads/master@{#294446}