Enable TETHER_ENABLE_SYNC_SM by default

The tether_enable_sync_sm flag has been successfully rolled out
to public stage on Pixel devices without any observed
regressions. As a result, this flag should be enabled by default
with a kill switch, allowing the feature to be deployed to all
production devices.

Test: atest TetheringTests CtsTetheringTest
Change-Id: I2f0f55c1586e1f4987b28488082c4c1f4cae0f5e
diff --git a/Tethering/src/com/android/networkstack/tethering/TetheringConfiguration.java b/Tethering/src/com/android/networkstack/tethering/TetheringConfiguration.java
index b3e9c1b..85036c2 100644
--- a/Tethering/src/com/android/networkstack/tethering/TetheringConfiguration.java
+++ b/Tethering/src/com/android/networkstack/tethering/TetheringConfiguration.java
@@ -142,7 +142,7 @@
     public static final int DEFAULT_TETHER_OFFLOAD_POLL_INTERVAL_MS = 5000;
 
     /** A flag for using synchronous or asynchronous state machine. */
-    public static boolean USE_SYNC_SM = false;
+    public static boolean USE_SYNC_SM = true;
 
     /**
      * A feature flag to control whether the active sessions metrics should be enabled.
@@ -195,6 +195,10 @@
             return DeviceConfigUtils.isTetheringFeatureEnabled(context, name);
         }
 
+        boolean isFeatureNotChickenedOut(@NonNull Context context, @NonNull String name) {
+            return DeviceConfigUtils.isTetheringFeatureNotChickenedOut(context, name);
+        }
+
         boolean getDeviceConfigBoolean(@NonNull String namespace, @NonNull String name,
                 boolean defaultValue) {
             return DeviceConfig.getBoolean(namespace, name, defaultValue);
@@ -394,7 +398,7 @@
      * use the async state machine.
      */
     public void readEnableSyncSM(final Context ctx) {
-        USE_SYNC_SM = mDeps.isFeatureEnabled(ctx, TETHER_ENABLE_SYNC_SM);
+        USE_SYNC_SM = mDeps.isFeatureNotChickenedOut(ctx, TETHER_ENABLE_SYNC_SM);
     }
 
     /** Does the dumping.*/
diff --git a/Tethering/tests/unit/src/com/android/networkstack/tethering/FakeTetheringConfiguration.java b/Tethering/tests/unit/src/com/android/networkstack/tethering/FakeTetheringConfiguration.java
index 087be26..c97fa3d 100644
--- a/Tethering/tests/unit/src/com/android/networkstack/tethering/FakeTetheringConfiguration.java
+++ b/Tethering/tests/unit/src/com/android/networkstack/tethering/FakeTetheringConfiguration.java
@@ -33,6 +33,11 @@
             }
 
             @Override
+            boolean isFeatureNotChickenedOut(@NonNull Context context, @NonNull String name) {
+                return true;
+            }
+
+            @Override
             boolean getDeviceConfigBoolean(@NonNull String namespace, @NonNull String name,
                     boolean defaultValue) {
                 return defaultValue;
diff --git a/Tethering/tests/unit/src/com/android/networkstack/tethering/TetheringConfigurationTest.java b/Tethering/tests/unit/src/com/android/networkstack/tethering/TetheringConfigurationTest.java
index dd51c7a..0159573 100644
--- a/Tethering/tests/unit/src/com/android/networkstack/tethering/TetheringConfigurationTest.java
+++ b/Tethering/tests/unit/src/com/android/networkstack/tethering/TetheringConfigurationTest.java
@@ -160,6 +160,11 @@
         }
 
         @Override
+        boolean isFeatureNotChickenedOut(@NonNull Context context, @NonNull String name) {
+            return isMockFlagEnabled(name, true /* defaultEnabled */);
+        }
+
+        @Override
         boolean getDeviceConfigBoolean(@NonNull String namespace, @NonNull String name,
                 boolean defaultValue) {
             // Flags should use isFeatureEnabled instead of getBoolean; see comments in
@@ -767,9 +772,9 @@
 
     @Test
     public void testEnableSyncSMFlag() throws Exception {
-        // Test default disabled
+        // Test default enabled
         setTetherEnableSyncSMFlagEnabled(null);
-        assertEnableSyncSM(false);
+        assertEnableSyncSM(true);
 
         setTetherEnableSyncSMFlagEnabled(true);
         assertEnableSyncSM(true);