Implement deletion of storage per site.

chrome/browser/storage/storage_info_fetcher.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 CHROME_BROWSER_STORAGE_STORAGE_INFO_FETCHER_H_
 #define CHROME_BROWSER_STORAGE_STORAGE_INFO_FETCHER_H_
 
 #include "base/memory/ref_counted.h"
 #include "storage/browser/quota/quota_manager.h"
 
 // Asynchronously fetches the amount of storage used by websites.
 class StorageInfoFetcher :
     public base::RefCountedThreadSafe<StorageInfoFetcher> {
  public:
   // Observer interface for monitoring StorageInfoFetcher.
   class Observer {
    public:
     // Called when the storage has been calculated.
     virtual void OnGetUsageInfo(const storage::UsageInfoEntries& entries) = 0;
 
+    // Called when the storage has been cleared.
+    virtual void OnUsageInfoCleared() = 0;

[michaelpg, 2016/02/03 18:39:13]

If this isn't used yet, add it in a later patch when you need it.

[Finnur, 2016/02/04 14:56:58]

It is used in the latest version of this patch.

+
    protected:
     virtual ~Observer() {}
   };
 
   explicit StorageInfoFetcher(storage::QuotaManager* quota_manager);
 
   // Asynchronously fetches the StorageInfo.
-  void Run();
+  void FetchStorageInfo();
+
+  // Asynchronously clears storage for the given host.
+  void ClearStorage(const std::string& host, storage::StorageType type);
+
+  // Called when usage has been cleared.
+  void OnUsageCleared(storage::QuotaStatusCode code);
 
   void AddObserver(Observer* observer);
   void RemoveObserver(Observer* observer);
 
  private:
   virtual ~StorageInfoFetcher();
 
   friend class base::RefCountedThreadSafe<StorageInfoFetcher>;
 
   // Fetches the usage information.
@@ skipping 11 matching lines @@
   // The quota manager to use to calculate the storage usage.
   storage::QuotaManager* quota_manager_;
 
   // Hosts and their usage.
   storage::UsageInfoEntries entries_;
 
   DISALLOW_COPY_AND_ASSIGN(StorageInfoFetcher);
 };
 
 #endif  // CHROME_BROWSER_STORAGE_STORAGE_INFO_FETCHER_H_