Disable task snapshots on svelte

Test: Boot low ram device, make sure cache stays empty
Bug: 31339431
Change-Id: I0fac1071f17fcd13872ef68f68eee2c793c6753c

services/core/java/com/android/server/wm/TaskSnapshotController.java

@@ -19,6 +19,7 @@ package com.android.server.wm;
 import static android.app.ActivityManager.ENABLE_TASK_SNAPSHOTS;
 
 import android.annotation.Nullable;
+import android.app.ActivityManager;
 import android.app.ActivityManager.StackId;
 import android.app.ActivityManager.TaskSnapshot;
 import android.graphics.GraphicBuffer;
@@ -65,26 +66,22 @@ class TaskSnapshotController {
     }
 
     void onTransitionStarting() {
-        if (!ENABLE_TASK_SNAPSHOTS) {
-            return;
-        }
         handleClosingApps(mService.mClosingApps);
     }
 
-
     /**
      * Called when the visibility of an app changes outside of the regular app transition flow.
      */
     void notifyAppVisibilityChanged(AppWindowToken appWindowToken, boolean visible) {
-        if (!ENABLE_TASK_SNAPSHOTS) {
-            return;
-        }
         if (!visible) {
             handleClosingApps(Sets.newArraySet(appWindowToken));
         }
     }
 
     private void handleClosingApps(ArraySet<AppWindowToken> closingApps) {
+        if (!ENABLE_TASK_SNAPSHOTS || ActivityManager.isLowRamDeviceStatic()) {
+            return;
+        }
 
         // We need to take a snapshot of the task if and only if all activities of the task are
         // either closing or hidden.