Trebuchet : Avoid unecessary generatePressedFocusedStates

When the drawable's state changes, don't generate state
drawables until after the invalidate call, which takes care of this
already, otherwise it gets drawn before measure/layout gets a chance to run.

Change-Id: I1ce89fffaa535f5c47e42ec64801a70cbc3f7814
Merge branch "cm-11.0" into kylin