Add sysprop to force enabling stylus pointer icon for debugging

This will make developing and testing the stylus pointer icon pipeline
easier.

Bug: 274664001
Test: adb shell setprop
persist.debug.input.force_enable_stylus_pointer_icon 1

Change-Id: I893a11140c18f28a8b04186a225de882fef5dad4
diff --git a/core/java/android/hardware/input/InputManager.java b/core/java/android/hardware/input/InputManager.java
index e7385b6..9cacfff 100644
--- a/core/java/android/hardware/input/InputManager.java
+++ b/core/java/android/hardware/input/InputManager.java
@@ -39,6 +39,7 @@
 import android.os.RemoteException;
 import android.os.SystemClock;
 import android.os.Vibrator;
+import android.sysprop.InputProperties;
 import android.util.Log;
 import android.view.Display;
 import android.view.InputDevice;
@@ -1123,7 +1124,8 @@
     public boolean isStylusPointerIconEnabled() {
         if (mIsStylusPointerIconEnabled == null) {
             mIsStylusPointerIconEnabled = getContext().getResources()
-                    .getBoolean(com.android.internal.R.bool.config_enableStylusPointerIcon);
+                    .getBoolean(com.android.internal.R.bool.config_enableStylusPointerIcon)
+                    || InputProperties.force_enable_stylus_pointer_icon().orElse(false);
         }
         return mIsStylusPointerIconEnabled;
     }