[CacheStorage] Keep caches alive for 30 seconds after opening

content/browser/cache_storage/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_CACHE_STORAGE_CACHE_STORAGE_H_
 #define CONTENT_BROWSER_CACHE_STORAGE_CACHE_STORAGE_H_
 
 #include <map>
 #include <string>
 
@@ skipping 84 matching lines @@
   // The size of all of the origin's contents in memory. Returns 0 if the cache
   // backend is not a memory backend. Runs synchronously.
   int64 MemoryBackedSize() const;
 
   // The functions below are for tests to verify that the operations run
   // serially.
   void StartAsyncOperationForTesting();
   void CompleteAsyncOperationForTesting();
 
  private:
+  friend class TestCacheStorage;
+
   class MemoryLoader;
   class SimpleCacheLoader;
   class CacheLoader;
 
   typedef std::map<std::string, base::WeakPtr<CacheStorageCache>> CacheMap;
 
   // Return a CacheStorageCache for the given name if the name is known. If the
   // CacheStorageCache has been deleted, creates a new one.
   scoped_refptr<CacheStorageCache> GetLoadedCache(
       const std::string& cache_name);
 
+  // Holds a reference to a cache for thirty seconds.
+  void TemporarilyPreserveCache(const scoped_refptr<CacheStorageCache>& cache);
+  virtual void SchedulePreservedCacheRemoval(
+      const base::Closure& callback);  // Virtual for testing.
+  void RemovePreservedCache(const CacheStorageCache* cache);
+
   // Initializer and its callback are below.
   void LazyInit();
   void LazyInitImpl();
   void LazyInitDidLoadIndex(
       scoped_ptr<std::vector<std::string>> indexed_cache_names);
 
   // The Open and CreateCache callbacks are below.
   void OpenCacheImpl(const std::string& cache_name,
                      const CacheAndErrorCallback& callback);
   void CreateCacheDidCreateCache(const std::string& cache_name,
@@ skipping 84 matching lines @@
 
   // The TaskRunner to run file IO on.
   scoped_refptr<base::SequencedTaskRunner> cache_task_runner_;
 
   // Whether or not to store data in disk or memory.
   bool memory_only_;
 
   // Performs backend specific operations (memory vs disk).
   scoped_ptr<CacheLoader> cache_loader_;
 
+  // Holds ref pointers to recently opened caches so that they can be reused
+  // without having the open the cache again.
+  std::map<const CacheStorageCache*, scoped_refptr<CacheStorageCache>>
+      preserved_caches_;
+
   base::WeakPtrFactory<CacheStorage> weak_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(CacheStorage);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_BROWSER_CACHE_STORAGE_CACHE_STORAGE_H_