AM: make isHighEndGfx TestApi

Bug: 136784434
Test: n/a
Change-Id: Ie26de8dcf64a02b7757d4f705485cdcb7470f511
diff --git a/api/test-current.txt b/api/test-current.txt
index 6f0b6a8..cb3674b 100644
--- a/api/test-current.txt
+++ b/api/test-current.txt
@@ -54,6 +54,7 @@
     method @RequiresPermission(android.Manifest.permission.PACKAGE_USAGE_STATS) public int getPackageImportance(String);
     method public long getTotalRam();
     method @RequiresPermission(android.Manifest.permission.PACKAGE_USAGE_STATS) public int getUidImportance(int);
+    method public static boolean isHighEndGfx();
     method @RequiresPermission(android.Manifest.permission.PACKAGE_USAGE_STATS) public void removeOnUidImportanceListener(android.app.ActivityManager.OnUidImportanceListener);
     method public static void resumeAppSwitches() throws android.os.RemoteException;
     method @RequiresPermission(android.Manifest.permission.CHANGE_CONFIGURATION) public void scheduleApplicationInfoChanged(java.util.List<java.lang.String>, int);
diff --git a/core/java/android/app/ActivityManager.java b/core/java/android/app/ActivityManager.java
index 17368b7..91b98c7 100644
--- a/core/java/android/app/ActivityManager.java
+++ b/core/java/android/app/ActivityManager.java
@@ -925,7 +925,7 @@
      * (which tends to consume a lot more RAM).
      * @hide
      */
-    @UnsupportedAppUsage
+    @TestApi
     static public boolean isHighEndGfx() {
         return !isLowRamDeviceStatic()
                 && !RoSystemProperties.CONFIG_AVOID_GFX_ACCEL