Add feature flag for force L3 dev option

Bug: 301669353
Change-Id: I289bed846982e94584fdb067e84186a61587d578

Android.bp

@@ -82,6 +82,7 @@ android_library {
 
         // Settings dependencies
         "FingerprintManagerInteractor",
+        "MediaDrmSettingsFlagsLib",
         "Settings-change-ids",
         "SettingsLib",
         "SettingsLibActivityEmbedding",

aconfig/Android.bp

@@ -25,3 +25,14 @@ java_aconfig_library {
     name: "factory_reset_flags_lib",
     aconfig_declarations: "factory_reset_flags",
 }
+
+aconfig_declarations {
+    name: "media_drm_flags",
+    package: "com.android.settings.media_drm",
+    srcs: ["media_drm/*.aconfig"],
+}
+
+java_aconfig_library {
+    name: "MediaDrmSettingsFlagsLib",
+    aconfig_declarations: "media_drm_flags",
+}

aconfig/media_drm/settings_mediadrm_flag_declarations.aconfig

@@ -0,0 +1,8 @@
+package: "com.android.settings.media_drm"
+
+flag {
+    name: "force_l3_enabled"
+    namespace: "media_drm"
+    description: "Feature flag of forcing L3"
+    bug: "301669353"
+}

src/com/android/settings/development/widevine/ForceL3FallbackPreferenceController.java

@@ -18,17 +18,22 @@ package com.android.settings.development.widevine;
 
 import android.content.Context;
 import android.sysprop.WidevineProperties;
+import android.util.Log;
+
+import androidx.preference.Preference;
 
 import com.android.internal.annotations.VisibleForTesting;
 import com.android.settings.R;
 import com.android.settings.core.TogglePreferenceController;
 import com.android.settingslib.development.DevelopmentSettingsEnabler;
+import com.android.settings.media_drm.Flags;
 
 /**
  * The controller (in the Media Widevine settings) enforces L3 security level
 * of Widevine CDM.
 */
 public class ForceL3FallbackPreferenceController extends TogglePreferenceController {
+    private static final String TAG = "ForceL3FallbackPreferenceController";
 
     public ForceL3FallbackPreferenceController(Context context, String preferenceKey) {
         super(context, preferenceKey);
@@ -45,6 +50,20 @@ public class ForceL3FallbackPreferenceController extends TogglePreferenceControl
         return true;
     }
 
+    @Override
+    public void updateState(Preference preference) {
+        if (Flags.forceL3Enabled()) {
+            preference.setEnabled(true);
+            Log.i(TAG, "forceL3Enabled is on");
+        } else {
+            preference.setEnabled(false);
+            // In case of flag rollback, the controller should be unchecked.
+            WidevineProperties.forcel3_enabled(false);
+            Log.i(TAG, "forceL3Enabled is off");
+        }
+        super.updateState(preference);
+    }
+
     @Override
     public int getAvailabilityStatus() {
         if (DevelopmentSettingsEnabler.isDevelopmentSettingsEnabled(mContext)) {