ozone: evdev: Add a couple more trace events

ozone: evdev: Add a couple more trace events

Add trace event inside each read notification for evdev.

BUG=none
TEST=chrome://tracing in link_freon

Committed: https://crrev.com/c4363d1ca65494cb7b271625e1ff6541a9f593c9
Cr-Commit-Position: refs/heads/master@{#327110}

[spang, 2015-04-27 19:38:58]

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

[kpschoedel, 2015-04-27 19:41:33]

lgtm

[spang, 2015-04-27 19:42:28]

The CQ bit was checked by spang@chromium.org

[commit-bot: I haz the power, 2015-04-27 19:43:06]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1110693003/1

[commit-bot: I haz the power, 2015-04-27 20:08:18]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-04-27 20:09:12]

Patchset 1 (id:??) landed as
https://crrev.com/c4363d1ca65494cb7b271625e1ff6541a9f593c9
Cr-Commit-Position: refs/heads/master@{#327110}