Base: respect layout changes before sending color broadcast

currently tinted system bar process is smart enough to determine
   when system bar need to change the background color
   now this patch improve how this process is done when when there is
   layout or window changes

example:
   open app, press home button
   open other app, press home button
   open recent or Omniswitch, open one of apps in there
   open again recent or Omniswitch, open other apps
   now system bar will take responsibility to changes the background color

another example:
   open app that has many activities like G+
   open notifications menu or input a message to post
   see system bar will take this layout transition to changes background color

for a scroll view, currently still need a touch to take process, because
   "View" is not a layout transition, so there is no way to take this to call tinted
   system bar process

fix notifications icon color not update after added
cleanup unused function

Change-Id: I0c69ad963d1589d6aad7c0135ed1007cbd2b4bba