Add a native aidl API.

Introduce a platform_compat_native service that just calls the
platform_compat service.
The new service is needed as it needs a slightly different (more
limited, no ApplicationInfo in cpp) aidl API, and a class can only
extend one stub.

Test: Call the service from dumpsys.cpp (http://aosp/1142055)
Bug: 138275545
Change-Id: Ic46cc34b4c1dd4ebc6bcc996fb3f8503607214ac

native/android/Android.bp

@@ -110,3 +110,36 @@ llndk_library {
     symbol_file: "libandroid_net.map.txt",
     unversioned: true,
 }
+
+
+// Aidl library for platform compat.
+cc_library_shared {
+    name: "lib-platform-compat-native-api",
+    cflags: [
+            "-Wall",
+            "-Werror",
+            "-Wno-missing-field-initializers",
+            "-Wno-unused-variable",
+            "-Wunused-parameter",
+        ],
+    shared_libs: [
+        "libbinder",
+         "libutils",
+    ],
+    aidl: {
+        local_include_dirs: ["aidl"],
+        export_aidl_headers: true,
+    },
+    srcs: [
+         ":platform-compat-native-aidl",
+    ],
+    export_include_dirs: ["aidl"],
+}
+
+filegroup {
+    name: "platform-compat-native-aidl",
+    srcs: [
+        "aidl/com/android/internal/compat/IPlatformCompatNative.aidl",
+    ],
+    path: "aidl",
+}

native/android/aidl/com/android/internal/compat/IPlatformCompatNative.aidl

@@ -0,0 +1,91 @@
+/*
+ * Copyright (C) 2019 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.internal.compat;
+
+/**
+ * Platform native private API for talking with the PlatformCompat service.
+ *
+ * <p> Should be used for gating and logging from non-app processes running cpp code.
+ * For app processes please use android.compat.Compatibility API.
+ *
+ * {@hide}
+ */
+interface IPlatformCompatNative
+{
+    /**
+     * Reports that a compatibility change is affecting an app process now.
+     *
+     * <p>Note: for changes that are gated using {@link #isChangeEnabled(long, String)},
+     * you do not need to call this API directly. The change will be reported for you.
+     *
+     * @param changeId    The ID of the compatibility change taking effect.
+     * @param packageName The package name of the app in question.
+     */
+     void reportChangeByPackageName(long changeId, @utf8InCpp String packageName);
+
+    /**
+     * Reports that a compatibility change is affecting an app process now.
+     *
+     * <p>Note: for changes that are gated using {@link #isChangeEnabled(long, int)},
+     * you do not need to call this API directly. The change will be reported for you.
+     *
+     * @param changeId The ID of the compatibility change taking effect.
+     * @param uid      The UID of the app in question.
+     */
+    void reportChangeByUid(long changeId, int uid);
+
+    /**
+     * Query if a given compatibility change is enabled for an app process. This method should
+     * be called when implementing functionality on behalf of the affected app.
+     *
+     * <p>Returns {@code true} if there is no installed package by the provided package name.
+     *
+     * <p>If this method returns {@code true}, the calling code should implement the compatibility
+     * change, resulting in differing behaviour compared to earlier releases. If this method
+     * returns
+     * {@code false}, the calling code should behave as it did in earlier releases.
+     *
+     * <p>It will also report the change as {@link #reportChange(long, String)} would, so there is
+     * no need to call that method directly.
+     *
+     * @param changeId    The ID of the compatibility change in question.
+     * @param packageName The package name of the app in question.
+     * @return {@code true} if the change is enabled for the current app.
+     */
+    boolean isChangeEnabledByPackageName(long changeId, @utf8InCpp String packageName);
+
+    /**
+     * Query if a given compatibility change is enabled for an app process. This method should
+     * be called when implementing functionality on behalf of the affected app.
+     *
+     * <p> Returns {@code true} if there are no installed packages for the required UID, or if the
+     * change is enabled for ALL of the installed packages associated with the provided UID. Please
+     * use a more specific API if you want a different behaviour for multi-package UIDs.
+     *
+     * <p>If this method returns {@code true}, the calling code should implement the compatibility
+     * change, resulting in differing behaviour compared to earlier releases. If this method
+     * returns {@code false}, the calling code should behave as it did in earlier releases.
+     *
+     * <p>It will also report the change as {@link #reportChange(long, int)} would, so there is
+     * no need to call that method directly.
+     *
+     * @param changeId The ID of the compatibility change in question.
+     * @param uid      The UID of the app in question.
+     * @return {@code true} if the change is enabled for the current app.
+     */
+    boolean isChangeEnabledByUid(long changeId, int uid);
+}