This change reduces the number of layout files and make these
theme-generic. This might be very helpful to re-design suggestion
strip.
Bug: 4175031
Change-Id: Idca10a4aa0bf7ac496eedd1879311e59780a423b
Previously the key preview was implemented by PopupWindow. The key
preview popup window would be dismissed and shown each time the key
was released and pressed. It turned out that it was taking several
milliseconds.
This change implements the key preview by a simple TextView which will
be layout-ed at absolute coordinates within the screen FrameLayout.
And dismissing and showing the key preview is implemented by the
TextView's visibility.
This implementation needs careful coordination of candidates.xml
layout and LatinIME.onComputeInsets to control suggestion strip
visibility.
Bug: 4179964
Change-Id: Id6347cb35b91eb14ab20dd2f312e58b54b6625a7
