Add tool to check if other requests are still running

This is needed for the Lock.java enhancement where a lock will be implicitly
released if the request owning it dies.

No matter which solution we want for refactoring the Lock itself, we will need this class.

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Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=167600314

java/google/registry/request/RequestLogId.java

@@ -0,0 +1,31 @@
+// Copyright 2017 The Nomulus Authors. All Rights Reserved.
+//
+// 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 google.registry.request;
+
+import static java.lang.annotation.RetentionPolicy.RUNTIME;
+
+import java.lang.annotation.Documented;
+import java.lang.annotation.Retention;
+import javax.inject.Qualifier;
+
+/**
+ * Dagger qualifier for the AppEngine request_log_id.
+ *
+ * <p>This is the unique log identifier of the current request.
+ */
+@Retention(RUNTIME)
+@Qualifier
+@Documented
+public @interface RequestLogId {}