Add invalidation to url_response_disk_cache.

services/url_response_disk_cache/url_response_disk_cache_db.h

 // Copyright 2015 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 SERVICES_URL_RESPONSE_DISK_CACHE_URL_RESPONSE_DISK_CACHE_DB_H_
 #define SERVICES_URL_RESPONSE_DISK_CACHE_URL_RESPONSE_DISK_CACHE_DB_H_
 
 #include "base/files/file_path.h"
 #include "base/memory/linked_ptr.h"
 #include "base/memory/ref_counted.h"
@@ skipping 26 matching lines @@
   };
 
   // Constructs the database. |db_path| is the path to the leveldb database. If
   // the path exists, the database will be opened, otherwise it will be created.
   explicit URLResponseDiskCacheDB(const base::FilePath& db_path);
 
   // Set and get the version of the database.
   uint64_t GetVersion();
   void SetVersion(uint64_t version);
 
+  // Set and get an entry for a given key.
+  void Put(CacheKeyPtr key, CacheEntryPtr entry);
+  CacheEntryPtr Get(CacheKeyPtr key);
+
   // Put an entry for the given |request_origin| and |url|. Older entry for the
   // same |request_origin| and |url| will not be removed, but will be shadowed
   // by the new one.
   void PutNew(const std::string& request_origin,
               const std::string& url,
               CacheEntryPtr entry);
 
   // Returns the newest entry for the given |request_origin| and |url|, or null
-  // if none exist.
+  // if none exist. If |key| is not null and GetNewest returns an entry, |*key|
+  // will contain the actual key of the entry.
   CacheEntryPtr GetNewest(const std::string& request_origin,
-                          const std::string& url);
+                          const std::string& url,
+                          CacheKeyPtr* key);
 
   // Delete the entry for the given |key|.
   void Delete(CacheKeyPtr key);
 
   // Returns an iterator over all the entries in the database. For a given
   // |request_origin| and |url|, entries will be sorted from newest to oldest.
   // An iterator will not be invalidated nor any of its values will be modified
   // by further changes to the database.
   scoped_ptr<Iterator> GetIterator();
 
  private:
   friend class base::RefCountedThreadSafe<URLResponseDiskCacheDB>;
   ~URLResponseDiskCacheDB();
 
   scoped_ptr<leveldb::Comparator> comparator_;
   linked_ptr<leveldb::DB> db_;
 };
 
 }  // namespace
 
 #endif  // SERVICES_URL_RESPONSE_DISK_CACHE_URL_RESPONSE_DISK_CACHE_DB_H_