Support repurposing idle timer to work with kernel timer.

Idle timer would instead enable/disable hw vsyncs in accordance with
inactivity.

Bug: 130684082
Test: systrace
Change-Id: I289600fc41b7ded863c9486cf6c2ab6155b06550
diff --git a/services/surfaceflinger/sysprop/SurfaceFlingerProperties.sysprop b/services/surfaceflinger/sysprop/SurfaceFlingerProperties.sysprop
index d369096..bd8aacd 100644
--- a/services/surfaceflinger/sysprop/SurfaceFlingerProperties.sysprop
+++ b/services/surfaceflinger/sysprop/SurfaceFlingerProperties.sysprop
@@ -315,3 +315,13 @@
     access: Readonly
     prop_name: "ro.surface_flinger.protected_contents"
 }
+
+# Indicates whether Scheduler's idle timer should support a display driver timeout in the kernel.
+# The value of set_idle_timer_ms should be shorter in time than the timeout duration in the kernel.
+prop {
+    api_name: "support_kernel_idle_timer"
+    type: Boolean
+    scope: System
+    access: Readonly
+    prop_name: "ro.surface_flinger.support_kernel_idle_timer"
+}