aura: Remove event-dispatch methods from WindowTreeHostDelegate interface.

Update the aura::WindowTreeHost implementations to also be ui::EventSource, and
remove the event-dispatch related methods from the WindowTreeHostDelegate
interface. The implementation of the WindowTreeHostDelegate interface related to
event-dispatch in RootWindow uses ui::EventProcessor for dispatching events
anyway, and so it is a good time to remove this redundant code.

BUG=318879
[email protected]

Review URL: https://codereview.chromium.org/147203004

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@248154 0039d316-1c4b-4281-b951-d872f2087c98
50 files changed