Move QoS API classes to Connectivity

The classes were added in S and are used to back ConnectivityManager
APIs. Add them to the connectivity boundary as they belong together with
ConnectivityManager.

Bug: 181512874
Test: m
Change-Id: I03b5978949b200a72813d1ebc4812d851fe3df37
diff --git a/framework/src/android/net/QosCallback.java b/framework/src/android/net/QosCallback.java
new file mode 100644
index 0000000..22f06bc
--- /dev/null
+++ b/framework/src/android/net/QosCallback.java
@@ -0,0 +1,91 @@
+/*
+ * Copyright (C) 2020 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 android.net;
+
+import android.annotation.NonNull;
+import android.annotation.SystemApi;
+
+import java.util.concurrent.Executor;
+
+/**
+ * Receives Qos information given a {@link Network}.  The callback is registered with
+ * {@link ConnectivityManager#registerQosCallback}.
+ *
+ * <p>
+ * <br/>
+ * The callback will no longer receive calls if any of the following takes place:
+ * <ol>
+ * <li>{@link ConnectivityManager#unregisterQosCallback(QosCallback)} is called with the same
+ * callback instance.</li>
+ * <li>{@link QosCallback#onError(QosCallbackException)} is called.</li>
+ * <li>A network specific issue occurs.  eg. Congestion on a carrier network.</li>
+ * <li>The network registered with the callback has no associated QoS providers</li>
+ * </ul>
+ * {@hide}
+ */
+@SystemApi
+public abstract class QosCallback {
+    /**
+     * Invoked after an error occurs on a registered callback.  Once called, the callback is
+     * automatically unregistered and the callback will no longer receive calls.
+     *
+     * <p>The underlying exception can either be a runtime exception or a custom exception made for
+     * {@link QosCallback}. see: {@link QosCallbackException}.
+     *
+     * @param exception wraps the underlying cause
+     */
+    public void onError(@NonNull final QosCallbackException exception) {
+    }
+
+    /**
+     * Called when a Qos Session first becomes available to the callback or if its attributes have
+     * changed.
+     * <p>
+     * Note: The callback may be called multiple times with the same attributes.
+     *
+     * @param session the available session
+     * @param sessionAttributes the attributes of the session
+     */
+    public void onQosSessionAvailable(@NonNull final QosSession session,
+            @NonNull final QosSessionAttributes sessionAttributes) {
+    }
+
+    /**
+     * Called after a Qos Session is lost.
+     * <p>
+     * At least one call to
+     * {@link QosCallback#onQosSessionAvailable(QosSession, QosSessionAttributes)}
+     * with the same {@link QosSession} will precede a call to lost.
+     *
+     * @param session the lost session
+     */
+    public void onQosSessionLost(@NonNull final QosSession session) {
+    }
+
+    /**
+     * Thrown when there is a problem registering {@link QosCallback} with
+     * {@link ConnectivityManager#registerQosCallback(QosSocketInfo, QosCallback, Executor)}.
+     */
+    public static class QosCallbackRegistrationException extends RuntimeException {
+        /**
+         * @hide
+         */
+        public QosCallbackRegistrationException() {
+            super();
+        }
+    }
+}