Default system theme should be DeviceDefault

Bug: 28796004
Change-Id: I33f9c064dd30d7fd96f06a8872765ddccf8a16a4
diff --git a/services/java/com/android/server/SystemServer.java b/services/java/com/android/server/SystemServer.java
index e306d89..eed4351 100644
--- a/services/java/com/android/server/SystemServer.java
+++ b/services/java/com/android/server/SystemServer.java
@@ -176,7 +176,7 @@
      * visual content.
      */
     private static final int DEFAULT_SYSTEM_THEME =
-            com.android.internal.R.style.Theme_Material_Light_DarkActionBar;
+            com.android.internal.R.style.Theme_DeviceDefault_Light_DarkActionBar;
 
     private final int mFactoryTestMode;
     private Timer mProfilerSnapshotTimer;