Add experiment flag namespace for Multi-Gen LRU

For testing Multi-Gen LRU page reclaim

Bug: 227651406
Test: adb shell device_config put mglru_native lru_gen_enabled [none, core, ..., all]
Test: verify MG RLU is enabled/disabled: cat /sys/kernel/mm/lru_gen/enabled
Change-Id: I2aa7032de2c45385e4c0ada787ba7799e50c8a53

core/java/android/provider/DeviceConfig.java

@@ -305,6 +305,13 @@ public final class DeviceConfig {
     @SystemApi
     public static final String NAMESPACE_MEDIA_NATIVE = "media_native";
 
+    /**
+     * Namespace for all Kernel Multi-Gen LRU feature.
+     *
+     * @hide
+     */
+    public static final String NAMESPACE_MGLRU_NATIVE = "mglru_native";
+
     /**
      * Namespace for all netd related features.
      *

services/core/java/com/android/server/am/SettingsToPropertiesMapper.java

@@ -86,6 +86,7 @@ public class SettingsToPropertiesMapper {
         DeviceConfig.NAMESPACE_INTELLIGENCE_CONTENT_SUGGESTIONS,
         DeviceConfig.NAMESPACE_LMKD_NATIVE,
         DeviceConfig.NAMESPACE_MEDIA_NATIVE,
+        DeviceConfig.NAMESPACE_MGLRU_NATIVE,
         DeviceConfig.NAMESPACE_NETD_NATIVE,
         DeviceConfig.NAMESPACE_NNAPI_NATIVE,
         DeviceConfig.NAMESPACE_PROFCOLLECT_NATIVE_BOOT,