Attempt to use dictionary facilitor without invoking
preference manager. Instead use account from settings only when
things are being reset/changed. Discussion forked from ag/591663

Overall, the idea here is to maintain an account information
inside dictionary groups. Reset the dictionary groups if
account changes (the way we do for locale). Since only user
history dictionary is currently affected, the check to reset user
history dictionary also includes the check to verify the account.
For other things remain the same.

SettingsValues holds the current account (and is updated if prefs change
due to change in account settings). The updated settings are then
propagated to dictionary facilitator via LatinIME#loadSettings.

Bug:18104749,18469539
Change-Id: I553e776e7ea125d0fb7a1fe70a4c7eb0b2277fb8