[bc25] Add a helper for reading and using the Dual Shade aconfig flag.

The first usage will be included in an upcoming follow-up CL.

Test: It builds.
Bug: 337021582.
Flag: ACONFIG com.android.systemui.dual_shade DISABLED
Change-Id: Ibe9c091572882cfe5cf70c58ac12b77128b37727

1 files changed, 56 insertions, 0 deletions

diff --git a/packages/SystemUI/src/com/android/systemui/shade/shared/flag/DualShade.kt b/packages/SystemUI/src/com/android/systemui/shade/shared/flag/DualShade.kt
new file mode 100644
index 000000000000..4db40582def4
--- /dev/null
+++ b/packages/SystemUI/src/com/android/systemui/shade/shared/flag/DualShade.kt
@@ -0,0 +1,56 @@
+/*
+ * Copyright (C) 2024 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.android.systemui.shade.shared.flag
+
+import com.android.systemui.Flags
+import com.android.systemui.flags.FlagToken
+import com.android.systemui.flags.RefactorFlagUtils
+
+/** Helper for reading and using the Dual Shade feature flag. */
+object DualShade {
+
+    /** The aconfig flag name. */
+    const val FLAG_NAME = Flags.FLAG_DUAL_SHADE
+
+    /** The flag description -- not an aconfig flag name. */
+    const val DESCRIPTION = "DualShadeFlag"
+
+    /** A token used for dependency declaration. */
+    val token: FlagToken
+        get() = FlagToken(FLAG_NAME, isEnabled)
+
+    /** Whether the feature is enabled. */
+    @JvmStatic
+    inline val isEnabled
+        get() = Flags.dualShade()
+
+    /**
+     * Called to ensure code is only run when the flag is enabled. This protects users from the
+     * unintended behaviors caused by accidentally running new logic, while also crashing on an eng
+     * build to ensure that the refactor author catches issues in testing.
+     */
+    @JvmStatic
+    fun isUnexpectedlyInLegacyMode() =
+        RefactorFlagUtils.isUnexpectedlyInLegacyMode(isEnabled, DESCRIPTION)
+
+    /**
+     * Called to ensure code is only run when the flag is disabled. This will throw an exception if
+     * the flag is enabled to ensure that the refactor author catches issues in testing.
+     */
+    @JvmStatic
+    fun assertInLegacyMode() = RefactorFlagUtils.assertInLegacyMode(isEnabled, DESCRIPTION)
+}