Adding shortcut on/off switch, improving the service picker,
and adding a switch to enable the shortcut on the lock screen.
Also adjusted setting search code to avoid indexing the
accessibility shortcut aside from the main accessibility settings
page.
Bug: 35872328
Bug: 35219988
Test: Ran in a variety of conditions, ran existing settings test.
Also added basic robo test, verified existing robo tests pass.
Change-Id: I4da9bad74caf96d9c8f3640e7db5417b4ee5d602
Repurposing shortcut setting to make it configurable.
Bug: 30160335
Test: Verified that the setting dialog appears with both
default and newly added accessibility services. Toggled
services on and off, and verified that nothing happened
when the shortcut was disabled.
Change-Id: I14d00109212bdd4b7919b2d51f702c8f118007fa