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

content/browser/service_worker/service_worker_cache_storage.h

 // Copyright 2014 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_SERVICE_WORKER_CACHE_STORAGE_H_
 #define CONTENT_BROWSER_SERVICE_WORKER_SERVICE_WORKER_CACHE_STORAGE_H_
 
 #include <map>
 #include <string>
 
@@ skipping 67 matching lines @@
   void DeleteCache(const std::string& cache_name,
                    const BoolAndErrorCallback& callback);
 
   // Calls the callback with a vector of cache names (keys) available.
   void EnumerateCaches(const StringsAndErrorCallback& callback);
 
   // TODO(jkarlin): Add match() function.
 
   void CloseAllCaches();
 
+  // The size of all of the origin's contents in memory. Returns 0 if the cache
+  // backend is not a memory backend.
+  int64 MemoryBackedSize() const;
+
  private:
   class MemoryLoader;
   class SimpleCacheLoader;
   class CacheLoader;
 
   typedef std::map<std::string, base::WeakPtr<ServiceWorkerCache> > CacheMap;
 
   // Return a ServiceWorkerCache for the given name if the name is known. If the
   // ServiceWorkerCache has been deleted, creates a new one.
   scoped_refptr<ServiceWorkerCache> GetLoadedCache(
@@ skipping 50 matching lines @@
   scoped_ptr<CacheLoader> cache_loader_;
 
   base::WeakPtrFactory<ServiceWorkerCacheStorage> weak_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(ServiceWorkerCacheStorage);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_BROWSER_SERVICE_WORKER_SERVICE_WORKER_CACHE_STORAGE_H_