[A11y][Keyboard shortcuts] Add flag for TalkBack key gesture
* This adds a flag to enable just the TalkBack key gesture shortcut
individually.
* This separates out existing logic that tied together the key gestures
for TalkBack and Magnification.
* To avoid rolling back existing work for Magnification, the
enable_talkback_and_magnifier_key_gestures flag will be left named
as-is.
* Due to the necessity of showing the permissions warning dialog when
the TalkBack shortcut is added, the technical limitations on the
existing dialog that shows when TalkBack settings are enabled, and the
level of UI, behavior, and string change involved in enabling this
scenario, it is safest to enable this TalkBack key gesture separately.
Bug: 331682600
Bug: 439624730
Flag: com.android.hardware.input.enable_talkback_and_magnifier_key_gestures
Flag: com.android.hardware.input.enable_talkback_key_gestures
Test: Tested manually locally, updated AccessibilityManagerServiceTest
and KeyGestureControllerTests
Change-Id: I7f78e3bffdab1da10a8b4226bc76824bdb4205c4
7 files changed
