This change also introduces MiniKeyboardKeyDetector and
mini_keyboad_slide_allowance parameter to tune the key detection
behavior.
Bug: 2993769
Change-Id: I1932b0a382e172cb77b9e098ae182049c834dfe0
Also, tentatively added key detection allowance for below of the keys in mini popup keyboard.
bug: 2979407
Change-Id: I84794969facd929c84df23e0120d46dff71c6efb