service worker: Tweak some documentation.

content/browser/service_worker/embedded_worker_instance.h

 // Copyright 2013 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef CONTENT_BROWSER_SERVICE_WORKER_EMBEDDED_WORKER_INSTANCE_H_
 #define CONTENT_BROWSER_SERVICE_WORKER_EMBEDDED_WORKER_INSTANCE_H_
 
 #include <stdint.h>
 
 #include <memory>
@@ skipping 277 matching lines @@
   // ReleaseProcess() and invokes |callback| with |status|. May destroy |this|.
   void OnStartFailed(const StatusCallback& callback,
                      ServiceWorkerStatusCode status);
 
   // Returns the time elapsed since |step_time_| and updates |step_time_|
   // to the current time.
   base::TimeDelta UpdateStepTime();
 
   base::WeakPtr<ServiceWorkerContextCore> context_;
   scoped_refptr<EmbeddedWorkerRegistry> registry_;
+
+  // Unique within an EmbeddedWorkerRegistry.
   const int embedded_worker_id_;
+
   EmbeddedWorkerStatus status_;
   StartingPhase starting_phase_;
 
   // Current running information.
   std::unique_ptr<EmbeddedWorkerInstance::WorkerProcessHandle> process_handle_;
   int thread_id_;
   std::unique_ptr<shell::InterfaceRegistry> interface_registry_;
   std::unique_ptr<shell::InterfaceProvider> remote_interfaces_;
 
   // Whether devtools is attached or not.
@@ skipping 16 matching lines @@
   base::TimeTicks step_time_;
 
   base::WeakPtrFactory<EmbeddedWorkerInstance> weak_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(EmbeddedWorkerInstance);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_BROWSER_SERVICE_WORKER_EMBEDDED_WORKER_INSTANCE_H_