removed optimization during onLayout
removed optimization during onLayout

optimization in onLayout led to edge-cases where viewport was not
updated when changing zoom or position programmatically - this commit
should patch those instances.

b2b2244424/TileView,rfdy/TileView,jinhui185190197/TileView,hgl888/TileView,Androidbsw/TileView,lovely3x/TileView,qingsong-xu/TileView,mark-watkin/TileView,zhangjie1980/TileView,tieusangaka/TileView,chiemy/TileView