Elements on the subpage get disabled if there are no enabled shortcut targets for the relevant type.
In the case of A11y button, the items on its fragment become unsearchable when the setting is disabled.
Test: Manually verify conditions described above & in bug
Bug: 349180207
Flag: com.android.settings.accessibility.fix_a11y_settings_search
Change-Id: Id39e2eda6c9d1de4cdbfcbc22b8a1f443e2822d9
1. Add gesture preference controller for gesture navigation
2. Auto update the preview illustarion when screen reader is on
3. Auto update accessibility button title for system navigation
Bug: 190563948
Test: make RunSettingsRoboTests ROBOTEST_FILTER=AccessibilityButtonGesturePreferenceControllerTest ROBOTEST_FILTER=AccessibilityButtonPreviewPreferenceControllerTest ROBOTEST_FILTER=AccessibilityLayerDrawableTest ROBOTEST_FILTER=AccessibilityPreferenceControllerTest ROBOTEST_FILTER=AccessibilityButtonFooterPreferenceControllerTest
Change-Id: Ifa98fc029430d86d3143133b3203b239340f2e41