ExtensionStorageMonitor: use smaller, self-registering StorageObservers

storage/browser/quota/storage_monitor.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 STORAGE_BROWSER_QUOTA_STORAGE_MONITOR_H_
 #define STORAGE_BROWSER_QUOTA_STORAGE_MONITOR_H_
 
 #include <stdint.h>
 
 #include <map>
@@ skipping 113 matching lines @@
 // Manages the observers of a common storage type.
 class STORAGE_EXPORT StorageTypeObservers {
  public:
   explicit StorageTypeObservers(QuotaManager* quota_manager);
   virtual ~StorageTypeObservers();
 
   // Adds and removes an observer.
   void AddObserver(StorageObserver* observer,
                    const StorageObserver::MonitorParams& params);
   void RemoveObserver(StorageObserver* observer);
-  void RemoveObserverForFilter(StorageObserver* observer,
-                               const StorageObserver::Filter& filter);
 
   // Returns the observers of a specific host.
   const HostStorageObservers* GetHostObservers(const std::string& host) const;
 
   // Handles a usage change.
   void NotifyUsageChange(const StorageObserver::Filter& filter, int64_t delta);
 
  private:
   QuotaManager* quota_manager_;
   std::map<std::string, std::unique_ptr<HostStorageObservers>>
@@ skipping 27 matching lines @@
   QuotaManager* quota_manager_;
   std::map<StorageType, std::unique_ptr<StorageTypeObservers>>
       storage_type_observers_map_;
 
   DISALLOW_COPY_AND_ASSIGN(StorageMonitor);
 };
 
 }  // namespace storage
 
 #endif  // STORAGE_BROWSER_QUOTA_STORAGE_MONITOR_H_