Add a flag to control activity snapshot by default.

When the flag is enabled, system will capture activity snapshot for
close activity by default.

Bug: 259497289
Test: local override then verify activity snapshot is enabled.
Change-Id: I023ebd9dc5e2e29f3f79760c15ca3bf5de645c5d
diff --git a/core/java/android/window/flags/windowing_frontend.aconfig b/core/java/android/window/flags/windowing_frontend.aconfig
index 7f65c52..1e99b9b 100644
--- a/core/java/android/window/flags/windowing_frontend.aconfig
+++ b/core/java/android/window/flags/windowing_frontend.aconfig
@@ -58,4 +58,12 @@
     description: "Predictive back for system animations"
     bug: "309545085"
     is_fixed_read_only: true
+}
+
+flag {
+    name: "activity_snapshot_by_default"
+    namespace: "systemui"
+    description: "Enable record activity snapshot by default"
+    bug: "259497289"
+    is_fixed_read_only: true
 }
\ No newline at end of file
diff --git a/services/core/java/com/android/server/wm/ActivitySnapshotController.java b/services/core/java/com/android/server/wm/ActivitySnapshotController.java
index 86be6ba..7af494c 100644
--- a/services/core/java/com/android/server/wm/ActivitySnapshotController.java
+++ b/services/core/java/com/android/server/wm/ActivitySnapshotController.java
@@ -33,6 +33,7 @@
 import com.android.server.LocalServices;
 import com.android.server.pm.UserManagerInternal;
 import com.android.server.wm.BaseAppSnapshotPersister.PersistInfoProvider;
+import com.android.window.flags.Flags;
 
 import java.io.File;
 import java.util.ArrayList;
@@ -121,7 +122,8 @@
 
     // TODO remove when enabled
     static boolean isSnapshotEnabled() {
-        return SystemProperties.getInt("persist.wm.debug.activity_screenshot", 0) != 0;
+        return SystemProperties.getInt("persist.wm.debug.activity_screenshot", 0) != 0
+                || Flags.activitySnapshotByDefault();
     }
 
     static PersistInfoProvider createPersistInfoProvider(