[flexiglass] Moves hardcoded enabledness check into SceneContainerFlags.

Bug: 299199299
Test: N/A
Change-Id: Ib0cb5664631a9508921c8471dadfc5f290285d68
diff --git a/packages/SystemUI/src/com/android/systemui/scene/shared/flag/SceneContainerFlags.kt b/packages/SystemUI/src/com/android/systemui/scene/shared/flag/SceneContainerFlags.kt
index 83fb723..291d273 100644
--- a/packages/SystemUI/src/com/android/systemui/scene/shared/flag/SceneContainerFlags.kt
+++ b/packages/SystemUI/src/com/android/systemui/scene/shared/flag/SceneContainerFlags.kt
@@ -69,7 +69,9 @@
             listOf(ComposeMustBeAvailable(), CompileTimeFlagMustBeEnabled())
 
     override fun isEnabled(): Boolean {
-        return requirements.all { it.isMet() }
+        // SCENE_CONTAINER_ENABLED is an explicit static flag check that helps with downstream
+        // optimizations, e.g., unused code stripping. Do not remove!
+        return Flags.SCENE_CONTAINER_ENABLED && requirements.all { it.isMet() }
     }
 
     override fun requirementDescription(): String {
diff --git a/packages/SystemUI/src/com/android/systemui/shade/ShadeViewProviderModule.kt b/packages/SystemUI/src/com/android/systemui/shade/ShadeViewProviderModule.kt
index f1e75b1..3f7512a 100644
--- a/packages/SystemUI/src/com/android/systemui/shade/ShadeViewProviderModule.kt
+++ b/packages/SystemUI/src/com/android/systemui/shade/ShadeViewProviderModule.kt
@@ -76,7 +76,7 @@
             scenesProvider: Provider<Set<@JvmSuppressWildcards Scene>>,
             layoutInsetController: NotificationInsetsController,
         ): WindowRootView {
-            return if (Flags.SCENE_CONTAINER_ENABLED && sceneContainerFlags.isEnabled()) {
+            return if (sceneContainerFlags.isEnabled()) {
                 val sceneWindowRootView =
                     layoutInflater.inflate(R.layout.scene_window_root, null) as SceneWindowRootView
                 sceneWindowRootView.init(