For #9782: Clean up unused FeatureFlags

I've currently found out this ones unused.
webPushIntegration removed because looks like all fatal bugs solved as it said from note.

app/src/main/java/org/mozilla/fenix/AppRequestInterceptor.kt

@@ -22,21 +22,8 @@ class AppRequestInterceptor(private val context: Context) : RequestInterceptor {
         hasUserGesture: Boolean,
         isSameDomain: Boolean
     ): RequestInterceptor.InterceptionResponse? {
-        var result: RequestInterceptor.InterceptionResponse? = null
-
-        // WebChannel-driven authentication does not require a separate redirect interceptor.
-        @Suppress("ConstantConditionIf")
-        if (FeatureFlags.asFeatureWebChannelsDisabled) {
-            result = context.components.services.accountsAuthFeature.interceptor.onLoadRequest(
-                    engineSession, uri, hasUserGesture, isSameDomain)
-        }
-
-        if (result == null) {
-            result = context.components.services.appLinksInterceptor.onLoadRequest(
-                engineSession, uri, hasUserGesture, isSameDomain)
-        }
-
-        return result
+        return context.components.services.appLinksInterceptor
+            .onLoadRequest(engineSession, uri, hasUserGesture, isSameDomain)
     }
 
     override fun onErrorRequest(

app/src/main/java/org/mozilla/fenix/FeatureFlags.kt

@@ -10,25 +10,6 @@ object FeatureFlags {
      */
     const val pullToRefreshEnabled = false
 
-    /**
-     * Disables FxA Application Services Web Channels feature
-     */
-    const val asFeatureWebChannelsDisabled = false
-
-    /**
-     * Disables FxA Application Services Sync feature
-     */
-    const val asFeatureSyncDisabled = false
-
-    /**
-     * Integration of push support provided by `feature-push` component into the Gecko engine.
-     *
-     * Behind nightly flag until all fatal bugs are resolved.
-     *
-     * https://github.com/mozilla-mobile/fenix/issues/9059
-     */
-    const val webPushIntegration = true
-
     /**
      * Enables tip feature
      */

app/src/main/java/org/mozilla/fenix/FenixApplication.kt

@@ -37,7 +37,6 @@ import mozilla.components.support.rusthttp.RustHttpConfig
 import mozilla.components.support.rustlog.RustLog
 import mozilla.components.support.utils.logElapsedTime
 import mozilla.components.support.webextensions.WebExtensionSupport
-import org.mozilla.fenix.FeatureFlags.webPushIntegration
 import org.mozilla.fenix.components.Components
 import org.mozilla.fenix.components.metrics.MetricServiceType
 import org.mozilla.fenix.ext.settings
@@ -239,10 +238,7 @@ open class FenixApplication : LocaleAwareApplication() {
             // Install the AutoPush singleton to receive messages.
             PushProcessor.install(it)
 
-            if (webPushIntegration) {
-                // WebPush integration to observe and deliver push messages to engine.
             WebPushEngineIntegration(components.core.engine, it).start()
-            }
 
             // Perform a one-time initialization of the account manager if a message is received.
             PushFxaIntegration(it, lazy { components.backgroundServices.accountManager }).launch()

app/src/main/java/org/mozilla/fenix/browser/BaseBrowserFragment.kt

@@ -560,8 +560,6 @@ abstract class BaseBrowserFragment : Fragment(), UserInteractionHandler, Session
                 view.swipeRefresh.setOnChildScrollUpCallback { _, _ -> true }
             }
 
-            @Suppress("ConstantConditionIf")
-            if (!FeatureFlags.asFeatureWebChannelsDisabled) {
             webchannelIntegration.set(
                 feature = FxaWebChannelFeature(
                     requireContext(),
@@ -575,7 +573,6 @@ abstract class BaseBrowserFragment : Fragment(), UserInteractionHandler, Session
                 owner = this,
                 view = view
             )
-            }
 
             initializeEngineView(toolbarHeight)
         }

app/src/main/java/org/mozilla/fenix/components/BackgroundServices.kt

@@ -84,20 +84,12 @@ class BackgroundServices(
     // If sync has been turned off on the server then disable syncing.
     @Suppress("ConstantConditionIf")
     @VisibleForTesting(otherwise = PRIVATE)
-    val syncConfig = if (FeatureFlags.asFeatureSyncDisabled) {
-        null
-    } else {
-
     val supportedEngines = if (FeatureFlags.syncedTabs) {
         setOf(SyncEngine.History, SyncEngine.Bookmarks, SyncEngine.Passwords, SyncEngine.Tabs)
     } else {
         setOf(SyncEngine.History, SyncEngine.Bookmarks, SyncEngine.Passwords)
     }
-
-        SyncConfig(
-            supportedEngines,
-            syncPeriodInMinutes = 240L) // four hours
-    }
+    private val syncConfig = SyncConfig(supportedEngines, syncPeriodInMinutes = 240L) // four hours
 
     init {
         /* Make the "history", "bookmark", "passwords", and "tabs" stores accessible to workers

app/src/main/java/org/mozilla/fenix/components/FxaServer.kt

@@ -6,7 +6,6 @@ package org.mozilla.fenix.components
 import android.content.Context
 import mozilla.components.service.fxa.ServerConfig
 import mozilla.components.service.fxa.ServerConfig.Server
-import org.mozilla.fenix.FeatureFlags
 import org.mozilla.fenix.ext.settings
 
 /**
@@ -14,22 +13,16 @@ import org.mozilla.fenix.ext.settings
  */
 
 object FxaServer {
-    const val CLIENT_ID = "a2270f727f45f648"
-    const val REDIRECT_URL = "https://accounts.firefox.com/oauth/success/$CLIENT_ID"
+    private const val CLIENT_ID = "a2270f727f45f648"
 
-    @Suppress("ConstantConditionIf", "UNUSED_PARAMETER")
-    fun redirectUrl(context: Context) = if (FeatureFlags.asFeatureWebChannelsDisabled) {
-        REDIRECT_URL
-    } else {
-        "urn:ietf:wg:oauth:2.0:oob:oauth-redirect-webchannel"
-    }
+    fun redirectUrl() = "urn:ietf:wg:oauth:2.0:oob:oauth-redirect-webchannel"
 
     fun config(context: Context): ServerConfig {
         val serverOverride = context.settings().overrideFxAServer
         val tokenServerOverride = context.settings().overrideSyncTokenServer.ifEmpty { null }
         if (serverOverride.isEmpty()) {
-            return ServerConfig(Server.RELEASE, CLIENT_ID, redirectUrl(context), tokenServerOverride)
+            return ServerConfig(Server.RELEASE, CLIENT_ID, redirectUrl(), tokenServerOverride)
         }
-        return ServerConfig(serverOverride, CLIENT_ID, redirectUrl(context), tokenServerOverride)
+        return ServerConfig(serverOverride, CLIENT_ID, redirectUrl(), tokenServerOverride)
     }
 }

app/src/main/java/org/mozilla/fenix/components/Services.kt

@@ -26,7 +26,7 @@ class Services(
     private val accountManager: FxaAccountManager
 ) {
     val accountsAuthFeature by lazy {
-        FirefoxAccountsAuthFeature(accountManager, FxaServer.redirectUrl(context)) { context, authUrl ->
+        FirefoxAccountsAuthFeature(accountManager, FxaServer.redirectUrl()) { context, authUrl ->
             CoroutineScope(Dispatchers.Main).launch {
                 val intent = SupportUtils.createAuthCustomTabIntent(context, authUrl)
                 context.startActivity(intent)