Add back render-ahead support

Currently only supported in the EGL path.
Vulkan support Coming Soon

Bug: 127822449
Test: trace of hwuimacro
Change-Id: Iac2b039e11d964aab5b8ca1bdf2a5430b187e2ea
diff --git a/libs/hwui/HWUIProperties.sysprop b/libs/hwui/HWUIProperties.sysprop
index 42191ca..34aeaae 100644
--- a/libs/hwui/HWUIProperties.sysprop
+++ b/libs/hwui/HWUIProperties.sysprop
@@ -7,3 +7,10 @@
     scope: Public
     access: Readonly
 }
+prop {
+    api_name: "render_ahead"
+    type: Integer
+    prop_name: "ro.hwui.render_ahead"
+    scope: Public
+    access: Readonly
+}
\ No newline at end of file