Interface for multiple virtual touchpads.

This passes the touchpad selection across binder, but does not yet
actually implement multiple touchpad devices.

Bug: b/35992608
Test: primary only in VirtualTouchpad_test
Change-Id: I7529735362e0e38805b9c0e52e07b5efc86bd535
diff --git a/services/vr/virtual_touchpad/VirtualTouchpadService.cpp b/services/vr/virtual_touchpad/VirtualTouchpadService.cpp
index 3fcb8fc..a1f281c 100644
--- a/services/vr/virtual_touchpad/VirtualTouchpadService.cpp
+++ b/services/vr/virtual_touchpad/VirtualTouchpadService.cpp
@@ -8,16 +8,15 @@
 namespace android {
 namespace dvr {
 
-binder::Status VirtualTouchpadService::touch(float x, float y, float pressure) {
-  const status_t error = touchpad_->Touch(x, y, pressure);
-  return error ? binder::Status::fromStatusT(error)
-               : binder::Status::ok();
+binder::Status VirtualTouchpadService::touch(int touchpad,
+                                             float x, float y, float pressure) {
+  const status_t error = touchpad_->Touch(touchpad, x, y, pressure);
+  return error ? binder::Status::fromStatusT(error) : binder::Status::ok();
 }
 
-binder::Status VirtualTouchpadService::buttonState(int buttons) {
-  const status_t error = touchpad_->ButtonState(buttons);
-  return error ? binder::Status::fromStatusT(error)
-               : binder::Status::ok();
+binder::Status VirtualTouchpadService::buttonState(int touchpad, int buttons) {
+  const status_t error = touchpad_->ButtonState(touchpad, buttons);
+  return error ? binder::Status::fromStatusT(error) : binder::Status::ok();
 }
 
 }  // namespace dvr