Add daily quota for precache

components/precache/core/precache_session_table.h

 // Copyright 2016 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 COMPONENTS_PRECACHE_CORE_PRECACHE_SESSION_TABLE_H_
 #define COMPONENTS_PRECACHE_CORE_PRECACHE_SESSION_TABLE_H_
 
 #include <list>
 #include <map>
 #include <memory>
 
 #include "base/macros.h"
 #include "base/time/time.h"
 #include "url/gurl.h"
 
 namespace base {
 class TimeTicks;
 }
 
 namespace sql {
 class Connection;
 }
 
 namespace precache {
 
 class PrecacheUnfinishedWork;
+class PrecacheQuota;
 
 // Denotes the type of session information being stored.
 enum SessionDataType {
   // Unfinished work to do sometime later.
   UNFINISHED_WORK = 0,
+
   // Timestamp of the last precache.
   LAST_PRECACHE_TIMESTAMP = 1,
+
+  // Remaining quota limits.
+  QUOTA = 2,
 };
 
 class PrecacheSessionTable {
  public:
   PrecacheSessionTable();
   virtual ~PrecacheSessionTable();
 
   // Initializes the precache task URL table for use with the specified database
   // connection. The caller keeps ownership of |db|, and |db| must not be null.
   // Init must be called before any other methods.
   bool Init(sql::Connection* db);
 
   // -- Time since last precache --
 
   void SetLastPrecacheTimestamp(const base::Time& time);
 
   // If none present, it will return base::Time(), so it can be checked via
   // is_null().
   base::Time GetLastPrecacheTimestamp();
 
   void DeleteLastPrecacheTimestamp();
 
+  // Precache quota.
+  void SaveQuota(const PrecacheQuota& quota);
+  PrecacheQuota GetQuota();
+
   // -- Unfinished work --
 
   // Stores unfinished work.
   void SaveUnfinishedWork(
       std::unique_ptr<PrecacheUnfinishedWork> unfinished_work);
 
   // Retrieves unfinished work.
   std::unique_ptr<PrecacheUnfinishedWork> GetUnfinishedWork();
 
   // Removes all unfinished work from the database.
   void DeleteUnfinishedWork();
 
  private:
   bool CreateTableIfNonExistent();
 
+  void SetSessionDataType(SessionDataType id, const std::string& data);
+  std::string GetSessionDataType(SessionDataType id);
+
   // Non-owned pointer.
   sql::Connection* db_;
 
   DISALLOW_COPY_AND_ASSIGN(PrecacheSessionTable);
 };
 
 }  // namespace precache
 #endif  // COMPONENTS_PRECACHE_CORE_PRECACHE_SESSION_TABLE_H_