ozone: Make the evdev implementation a PlatformEventSource.

ozone: Make the evdev implementation a PlatformEventSource.

Instead of using the EventFactoryOzone as the PlatformEventSource, allow
ozone's platform implementation to decide what to use as the event-source.
For the evdev ozone-platform, the event-factory (EventFactoryEvdev) remains
as the event source. In the case of X11 ozone-platform, it will create the
X11EventSource (currently used on chromeos and linux-aura) as the
event-source.

BUG=361137
R=spang@chromium.org

Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=269808

[rjkroege, 2014-05-12 12:35:17]

on the face of it, this change seems fine but the build bot result looks
suspicious? 

also: in case you might have forgotten, please remember to test with and without
evdev

[sadrul, 2014-05-12 15:22:31]

On 2014/05/12 12:35:17, rjkroege wrote:
> on the face of it, this change seems fine but the build bot result looks
> suspicious? 

The try failure is the same failure we have on the buildbot, and is unrelated to
this change.

> 
> also: in case you might have forgotten, please remember to test with and
without
> evdev

This change also works with the WIP x11 implementation. What other input
implementation should I test with?

[spang, 2014-05-12 16:31:13]

lgtm

[sadrul, 2014-05-12 17:43:45]

Committed patchset #1 manually as r269808 (presubmit successful).