Add IME switch button long click support
This adds support for handling long clicking on the IME switch button.
Initially it will behave exactly like short clicking, i.e. show the IME
switcher menu.
As the IME navigation bar didn't previously support long clicks, this
follows along the logic of the SystemUI navigation bar, with a small
modification: holding down the button for longer than the long click
timeout does not send a cancel event, to maintain the current behaviour
that holding down the IME dismiss button should still hide the IME.
Flag: android.view.inputmethod.ime_switcher_revamp
Test: atest
NavigationBarTest#testImeSwitcherClick
NavigationBarTest#testImeSwitcherLongClick
InputMethodServiceTest#testBackButtonClick
InputMethodServiceTest#testBackButtonLongClick
InputMethodServiceTest#testImeSwitchButtonClick
InputMethodServiceTest#testImeSwitchButtonLongClick
Bug: 311791923
Change-Id: I633da5b03fa50ec1ccf515a4df5538e397d15442
18 files changed
