Purge browser cache for dom storage in a smarter way

content/browser/dom_storage/dom_storage_database.h

 // Copyright 2013 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_DOM_STORAGE_DOM_STORAGE_DATABASE_H_
 #define CONTENT_BROWSER_DOM_STORAGE_DOM_STORAGE_DATABASE_H_
 
 #include <map>
 #include <memory>
 
@@ skipping 25 matching lines @@
 
   // Updates the backing database. Will remove all keys before updating
   // the database if |clear_all_first| is set. Then all entries in
   // |changes| will be examined - keys mapped to a null NullableString16
   // will be removed and all others will be inserted/updated as appropriate.
   bool CommitChanges(bool clear_all_first, const DOMStorageValuesMap& changes);
 
   // Simple getter for the path we were constructed with.
   const base::FilePath& file_path() const { return file_path_; }
 
+  // Reduce the size of sqlite caches.
+  void TrimMemory();
+
  protected:
   // Constructor that uses an in-memory sqlite database, for testing.
   DOMStorageDatabase();
 
  private:
   friend class LocalStorageDatabaseAdapter;
   FRIEND_TEST_ALL_PREFIXES(DOMStorageDatabaseTest, SimpleOpenAndClose);
   FRIEND_TEST_ALL_PREFIXES(DOMStorageDatabaseTest, TestLazyOpenIsLazy);
   FRIEND_TEST_ALL_PREFIXES(DOMStorageDatabaseTest, TestDetectSchemaVersion);
   FRIEND_TEST_ALL_PREFIXES(DOMStorageDatabaseTest,
@@ skipping 54 matching lines @@
   const base::FilePath file_path_;
   std::unique_ptr<sql::Connection> db_;
   bool failed_to_open_;
   bool tried_to_recreate_;
   bool known_to_be_empty_;
 };
 
 }  // namespace content
 
 #endif  // CONTENT_BROWSER_DOM_STORAGE_DOM_STORAGE_DATABASE_H_