Don't proceed with userspace reboot if device doesn't support it

Test: set property to false and adb reboot userspace
Bug: 135984674
Change-Id: I11e55243df002dd54e533a6b9fc529866597d4dd
diff --git a/init/sysprop/InitProperties.sysprop b/init/sysprop/InitProperties.sysprop
index d6a1ab6..c856358 100644
--- a/init/sysprop/InitProperties.sysprop
+++ b/init/sysprop/InitProperties.sysprop
@@ -25,3 +25,12 @@
     integer_as_bool: true
 }
 
+# Shows whenever the device supports userspace reboot or not.
+prop {
+    api_name: "is_userspace_reboot_supported"
+    type: Boolean
+    scope: System
+    access: Readonly
+    prop_name: "ro.init.userspace_reboot.is_supported"
+    integer_as_bool: true
+}
diff --git a/init/sysprop/api/com.android.sysprop.init-current.txt b/init/sysprop/api/com.android.sysprop.init-current.txt
index 8da50e0..b8bcef9 100644
--- a/init/sysprop/api/com.android.sysprop.init-current.txt
+++ b/init/sysprop/api/com.android.sysprop.init-current.txt
@@ -1,6 +1,11 @@
 props {
   module: "android.sysprop.InitProperties"
   prop {
+    api_name: "is_userspace_reboot_supported"
+    prop_name: "ro.init.userspace_reboot.is_supported"
+    integer_as_bool: true
+  }
+  prop {
     api_name: "userspace_reboot_in_progress"
     access: ReadWrite
     prop_name: "sys.init.userspace_reboot.in_progress"