[CacheStorage] Keep caches alive for 30 seconds after opening

content/browser/cache_storage/cache_storage.h

Index: content/browser/cache_storage/cache_storage.h
diff --git a/content/browser/cache_storage/cache_storage.h b/content/browser/cache_storage/cache_storage.h
index 6ec3e238dd05bfe52c16906b4fb3a5833b5a5476..b2ea3876ca059e0fbd268d20154067094ce34332 100644
--- a/content/browser/cache_storage/cache_storage.h
+++ b/content/browser/cache_storage/cache_storage.h
@@ -102,6 +102,8 @@ class CONTENT_EXPORT CacheStorage {
   void CompleteAsyncOperationForTesting();
 
  private:
+  friend class TestCacheStorage;
+
   class MemoryLoader;
   class SimpleCacheLoader;
   class CacheLoader;
@@ -113,6 +115,12 @@ class CONTENT_EXPORT CacheStorage {
   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();
@@ -217,6 +225,11 @@ class CONTENT_EXPORT CacheStorage {
   // 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);