Handle _NET_ACTIVE_WINDOW or FocusIn & FocusOut, not both.

When WM supports _NET_ACTIVE_WINDOW notification, we get OnActiveWindowChanged() from two places:
 - X11DesktopHandler::ProcessXEvent (FocusIn)
 - X11DesktopHandler::DispatchEvent (PropertyNotify)

One is enough, two can lead to confusion. FocusIn/Out should not be handled if WM supports active window.

BUG=None
TEST=None

Review URL: https://codereview.chromium.org/549713003

Cr-Commit-Position: refs/heads/master@{#294550}
1 file changed