[ServiceWorkerCache] Return the real size of the cache in GetOriginUsage.

content/browser/service_worker/service_worker_cache.h

Index: content/browser/service_worker/service_worker_cache.h
diff --git a/content/browser/service_worker/service_worker_cache.h b/content/browser/service_worker/service_worker_cache.h
index 65966090ed52ff3ea04054494ed698d72d2961cc..ae9b7f3d7fe6381af0f8d8b64fb150b9f84996b8 100644
--- a/content/browser/service_worker/service_worker_cache.h
+++ b/content/browser/service_worker/service_worker_cache.h
@@ -90,6 +90,10 @@ class CONTENT_EXPORT ServiceWorkerCache
   // Prevent further operations on this object and delete the backend.
   void Close();
 
+  // The size of the cache contents in memory. Returns 0 if the cache backend is
+  // not a memory cache backend.
+  int64 MemoryBackedSize() const;
+
   void set_backend(scoped_ptr<disk_cache::Backend> backend) {
     backend_ = backend.Pass();
   }
@@ -146,6 +150,9 @@ class CONTENT_EXPORT ServiceWorkerCache
   bool initialized_;
   std::vector<base::Closure> init_callbacks_;
 
+  // Whether or not to store data in disk or memory.
+  bool memory_only_;
+
   base::WeakPtrFactory<ServiceWorkerCache> weak_ptr_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(ServiceWorkerCache);