[CacheStorage] Prioritize Size operations over other scheduled operations

content/browser/cache_storage/cache_storage_cache.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_CACHE_STORAGE_CACHE_STORAGE_CACHE_H_
 #define CONTENT_BROWSER_CACHE_STORAGE_CACHE_STORAGE_CACHE_H_
 
 #include <stdint.h>
 
 #include <vector>
@@ skipping 93 matching lines @@
 
   // TODO(jkarlin): Have keys take an optional ServiceWorkerFetchRequest.
   // Returns CACHE_STORAGE_OK and a vector of requests if there are no errors.
   void Keys(const RequestsCallback& callback);
 
   // Closes the backend. Future operations that require the backend
   // will exit early. Close should only be called once per CacheStorageCache.
   void Close(const base::Closure& callback);
 
   // The size of the cache's contents. This runs in parallel with other Cache
-  // operations.
+  // operations. This is because QuotaManager is a dependency of the Put
+  // operation and QuotaManager calls Size. If the cache isn't yet initialized,
+  // runs immediately after initialization, before any pending operations in the
+  // scheduler are run.
   void Size(const SizeCallback& callback);
 
   // Gets the cache's size, closes the backend, and then runs |callback| with
   // the cache's size.
   void GetSizeThenClose(const SizeCallback& callback);
 
   base::FilePath path() const { return path_; }
 
   base::WeakPtr<CacheStorageCache> AsWeakPtr();
 
@@ skipping 166 matching lines @@
   // Be sure to check |backend_state_| before use.
   scoped_ptr<disk_cache::Backend> backend_;
 
   GURL origin_;
   base::FilePath path_;
   scoped_refptr<net::URLRequestContextGetter> request_context_getter_;
   scoped_refptr<storage::QuotaManagerProxy> quota_manager_proxy_;
   base::WeakPtr<storage::BlobStorageContext> blob_storage_context_;
   BackendState backend_state_ = BACKEND_UNINITIALIZED;
   scoped_ptr<CacheStorageScheduler> scheduler_;
+  std::vector<SizeCallback> pending_size_callbacks_;
   bool initializing_ = false;
   int64_t cache_size_ = 0;
 
   // Owns the elements of the list
   BlobToDiskCacheIDMap active_blob_to_disk_cache_writers_;
 
   // Whether or not to store data in disk or memory.
   bool memory_only_;
 
   base::WeakPtrFactory<CacheStorageCache> weak_ptr_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(CacheStorageCache);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_BROWSER_CACHE_STORAGE_CACHE_STORAGE_CACHE_H_