Remove undefined functions from VirtualTouchpadClient.

Fixes a build issue with -O0 due to missing vtable entries.
Removed functions are defined in the base class as pure virtual,
but never defined for the derived class, causing linking to fail.

Test: make NATIVE_COVERAGE=true COVERAGE_PATHS=frameworks
Bug: 116873221
Change-Id: I7ee8a2e478e1137e3b778dfbdca63a2dc3e2a9b1
(cherry picked from commit 29f76abd8385543d334e8c30e84a68e688a0dd41)
diff --git a/services/vr/virtual_touchpad/include/VirtualTouchpadClient.h b/services/vr/virtual_touchpad/include/VirtualTouchpadClient.h
index 7d73f06..268e4bd 100644
--- a/services/vr/virtual_touchpad/include/VirtualTouchpadClient.h
+++ b/services/vr/virtual_touchpad/include/VirtualTouchpadClient.h
@@ -13,12 +13,6 @@
  public:
   // VirtualTouchpad implementation:
   static std::unique_ptr<VirtualTouchpad> Create();
-  status_t Attach() override;
-  status_t Detach() override;
-  status_t Touch(int touchpad, float x, float y, float pressure) override;
-  status_t ButtonState(int touchpad, int buttons) override;
-  status_t Scroll(int touchpad, float x, float y) override;
-  void dumpInternal(String8& result) override;
 
  protected:
   VirtualTouchpadClient() {}