[ActivityManager] Move UI operation to UI handler

Because ANR will dump cpu usage, stack traces in ActivityManager
thread, if system is busy or in low-end device, it may spend more
than 5s to dump. So when there is UI operation (e.g. pop dialog)
in ActivityManager thread, it may meet key dispatch timeout.

Change-Id: Ie550e31a7cff65bdcfc9af2c32989e9deb5fb2cf
1 file changed