Split the event library into a cross-platform and native part. Part 1.

Split the event library into a cross-platform and native part. Part 1.

This removes construction of ui::Event and subclasses from
base::NativeEvents. It removes all usage of NativeEvents from that
file. It moves the code from there to the ui/events/platform/ directory,
which will eventually be its own library. The previous constructors have
been refactored into ui/events/platform/platform_event_builder.h. Tests
that relied on events were moved or rewritten.

Also adds events_unittests to the build.

BUG=443439
R=sky@chromium.org

Committed: https://chromium.googlesource.com/external/mojo/+/1f3263d89a45bedf1e7b125d5981827951ab54d7

[Elliot Glaysher, 2015-01-21 19:29:12]

erg@chromium.org changed reviewers:
+ sky@chromium.org

[Elliot Glaysher, 2015-01-21 20:58:14]

This is an awkward place to send this out for review, but it's a reasonable
milestone between nothing and changing the linkage and location of all the
platform specific code.

There are going to be followups; mainly moving all platform specific code (x/,
win/, maybe cocoa/ but I'll probably just drop that for now) to the
ui/events/platform/ directory where I'll make the platform specific code part of
the platform target, so that we can use the events library in mojo without
pulling in x11.

[sky, 2015-01-21 22:46:46]

LGTM

https://codereview.chromium.org/862093002/diff/40001/ui/events/event.h
File ui/events/event.h (right):

https://codereview.chromium.org/862093002/diff/40001/ui/events/event.h#newcod...
ui/events/event.h:268: gfx::Point screen_location() const { return
screen_location_; }
const gfx::Point&

https://codereview.chromium.org/862093002/diff/40001/ui/events/platform/platf...
File ui/events/platform/platform_event_builder.h (right):

https://codereview.chromium.org/862093002/diff/40001/ui/events/platform/platf...
ui/events/platform/platform_event_builder.h:65: };
DISALLOW_IMPLICIT_CONSTRUCTORS?

[Elliot Glaysher, 2015-01-21 23:13:02]

Committed patchset #5 (id:80001) manually as
1f3263d89a45bedf1e7b125d5981827951ab54d7 (presubmit successful).