Add flag for enabling only new storage and use in aflags

Change-Id: I73218de38d005d77987d5103364a102cec3abc07
Test: m && cargo t
Bug: 324436145
diff --git a/tools/aconfig/aconfig_flags/Android.bp b/tools/aconfig/aconfig_flags/Android.bp
new file mode 100644
index 0000000..e327ced
--- /dev/null
+++ b/tools/aconfig/aconfig_flags/Android.bp
@@ -0,0 +1,46 @@
+/*
+ * 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.
+ */
+
+rust_library {
+    name: "libaconfig_flags",
+    crate_name: "aconfig_flags",
+    srcs: [
+        "src/lib.rs",
+    ],
+    rustlibs: [
+        "libaconfig_flags_rust",
+    ],
+    host_supported: true,
+}
+
+aconfig_declarations {
+    name: "aconfig_flags",
+    package: "com.android.aconfig.flags",
+    container: "system",
+    srcs: ["flags.aconfig"],
+}
+
+rust_aconfig_library {
+    name: "libaconfig_flags_rust",
+    crate_name: "aconfig_flags_rust",
+    aconfig_declarations: "aconfig_flags",
+    host_supported: true,
+}
+
+cc_aconfig_library {
+    name: "libaconfig_flags_cc",
+    aconfig_declarations: "aconfig_flags",
+}
diff --git a/tools/aconfig/aconfig_flags/Cargo.toml b/tools/aconfig/aconfig_flags/Cargo.toml
new file mode 100644
index 0000000..6eb9f14
--- /dev/null
+++ b/tools/aconfig/aconfig_flags/Cargo.toml
@@ -0,0 +1,10 @@
+[package]
+name = "aconfig_flags"
+version = "0.1.0"
+edition = "2021"
+
+[features]
+default = ["cargo"]
+cargo = []
+
+[dependencies]
\ No newline at end of file
diff --git a/tools/aconfig/aconfig_flags/flags.aconfig b/tools/aconfig/aconfig_flags/flags.aconfig
new file mode 100644
index 0000000..db8b1b7
--- /dev/null
+++ b/tools/aconfig/aconfig_flags/flags.aconfig
@@ -0,0 +1,9 @@
+package: "com.android.aconfig.flags"
+container: "system"
+
+flag {
+  name: "enable_only_new_storage"
+  namespace: "core_experiments_team_internal"
+  bug: "312235596"
+  description: "When enabled, aconfig flags are read from the new aconfig storage only."
+}
diff --git a/tools/aconfig/aconfig_flags/src/lib.rs b/tools/aconfig/aconfig_flags/src/lib.rs
new file mode 100644
index 0000000..a607efb
--- /dev/null
+++ b/tools/aconfig/aconfig_flags/src/lib.rs
@@ -0,0 +1,47 @@
+/*
+ * 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.
+ */
+
+//! `aconfig_flags` is a crate for reading aconfig flags from Rust
+// When building with the Android tool-chain
+//
+//   - the flag functions will read from aconfig_flags_inner
+//   - the feature "cargo" will be disabled
+//
+// When building with cargo
+//
+//   - the flag functions will all return some trivial value, like true
+//   - the feature "cargo" will be enabled
+//
+// This module hides these differences from the rest of aconfig.
+
+/// Module used when building with the Android tool-chain
+#[cfg(not(feature = "cargo"))]
+pub mod auto_generated {
+    /// Returns the value for the enable_only_new_storage flag.
+    pub fn enable_only_new_storage() -> bool {
+        aconfig_flags_rust::enable_only_new_storage()
+    }
+}
+
+/// Module used when building with cargo
+#[cfg(feature = "cargo")]
+pub mod auto_generated {
+    /// Returns a placeholder value for the enable_only_new_storage flag.
+    pub fn enable_only_new_storage() -> bool {
+        // Used only to enable typechecking and testing with cargo
+        true
+    }
+}