Add UserHandle and BinderChannelCredentials to BinderChannelBuilder to support cross-user ondevice server.

Author: wwtbuaa01

binder/src/main/java/io/grpc/binder/BinderChannelCredentials.java

@@ -0,0 +1,66 @@
+/*
+ * Copyright 2022 The gRPC Authors
+ *
+ * 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 io.grpc.binder;
+
+import static com.google.common.base.Preconditions.checkNotNull;
+
+import android.content.ComponentName;
+import io.grpc.ChannelCredentials;
+import io.grpc.ExperimentalApi;
+import javax.annotation.Nullable;
+
+/** Additional arbitrary arguments to establish a Android binder connection channel. */
+@ExperimentalApi("https://github.com/grpc/grpc-java/issues/10173")
+public final class BinderChannelCredentials extends ChannelCredentials {
+
+  /**
+   * Creates the default BinderChannelCredentials.
+   *
+   * @return a BinderChannelCredentials
+   */
+  public static BinderChannelCredentials forDefault() {
+    return new BinderChannelCredentials(null);
+  }
+
+  /**
+   * Creates a BinderChannelCredentials to be used with DevicePolicyManager API.
+   *
+   * @param devicePolicyAdminComponentName the admin component to be specified with
+   *     DevicePolicyManager.bindDeviceAdminServiceAsUser API.
+   * @return a BinderChannelCredentials
+   */
+  public static BinderChannelCredentials forDevicePolicyAdmin(
+      ComponentName devicePolicyAdminComponentName) {
+    return new BinderChannelCredentials(devicePolicyAdminComponentName);
+  }
+
+  @Nullable private final ComponentName devicePolicyAdminComponentName;
+
+  private BinderChannelCredentials(@Nullable ComponentName devicePolicyAdminComponentName) {
+    this.devicePolicyAdminComponentName = devicePolicyAdminComponentName;
+  }
+
+  @Override
+  public ChannelCredentials withoutBearerTokens() {
+    return this;
+  }
+
+  @Nullable
+  public ComponentName getDevicePolicyAdminComponentName() {
+    return devicePolicyAdminComponentName;
+  }
+}