Use exist sf aconfig flag for display small area feature

Replace duplicate created flags under display_flags for small area
detection feature to already exist sf flag.

Bug: 298722189
Test: build
Change-Id: Ia819adfb439d5f88a4c329069838726396bcd695
diff --git a/AconfigFlags.bp b/AconfigFlags.bp
index e3cbd92..a4ba743 100644
--- a/AconfigFlags.bp
+++ b/AconfigFlags.bp
@@ -57,6 +57,7 @@
     ":android.service.autofill.flags-aconfig-java{.generated_srcjars}",
     ":com.android.net.flags-aconfig-java{.generated_srcjars}",
     ":device_policy_aconfig_flags_lib{.generated_srcjars}",
+    ":surfaceflinger_flags_java_lib{.generated_srcjars}",
 ]
 
 filegroup {
@@ -627,3 +628,10 @@
     aconfig_declarations: "android.app.smartspace.flags-aconfig",
     defaults: ["framework-minus-apex-aconfig-java-defaults"],
 }
+
+// SurfaceFlinger
+java_aconfig_library {
+    name: "surfaceflinger_flags_java_lib",
+    aconfig_declarations: "surfaceflinger_flags",
+    defaults: ["framework-minus-apex-aconfig-java-defaults"],
+}
diff --git a/services/core/java/com/android/server/display/feature/DisplayManagerFlags.java b/services/core/java/com/android/server/display/feature/DisplayManagerFlags.java
index 7f3ea6a..0d3e0bc 100644
--- a/services/core/java/com/android/server/display/feature/DisplayManagerFlags.java
+++ b/services/core/java/com/android/server/display/feature/DisplayManagerFlags.java
@@ -77,8 +77,8 @@
             Flags::enablePowerThrottlingClamper);
 
     private final FlagState mSmallAreaDetectionFlagState = new FlagState(
-            Flags.FLAG_ENABLE_SMALL_AREA_DETECTION,
-            Flags::enableSmallAreaDetection);
+            com.android.graphics.surfaceflinger.flags.Flags.FLAG_ENABLE_SMALL_AREA_DETECTION,
+            com.android.graphics.surfaceflinger.flags.Flags::enableSmallAreaDetection);
 
     /** Returns whether connected display management is enabled or not. */
     public boolean isConnectedDisplayManagementEnabled() {
diff --git a/services/core/java/com/android/server/display/feature/display_flags.aconfig b/services/core/java/com/android/server/display/feature/display_flags.aconfig
index 9141814..9ab9c9d 100644
--- a/services/core/java/com/android/server/display/feature/display_flags.aconfig
+++ b/services/core/java/com/android/server/display/feature/display_flags.aconfig
@@ -104,12 +104,3 @@
     bug: "211737588"
     is_fixed_read_only: true
 }
-
-flag {
-    name: "enable_small_area_detection"
-    namespace: "display_manager"
-    description: "Feature flag for SmallAreaDetection"
-    bug: "298722189"
-    is_fixed_read_only: true
-}
-