Not creating ClientUsageTracker for unsupported storage type.

webkit/browser/quota/quota_client.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 WEBKIT_BROWSER_QUOTA_QUOTA_CLIENT_H_
 #define WEBKIT_BROWSER_QUOTA_QUOTA_CLIENT_H_
 
 #include <list>
 #include <set>
 #include <string>
@@ skipping 51 matching lines @@
   // Note it is safe to fire the callback after the QuotaClient is destructed.
   virtual void GetOriginsForHost(StorageType type,
                                  const std::string& host,
                                  const GetOriginsCallback& callback) = 0;
 
   // Called by the QuotaManager.
   // Note it is safe to fire the callback after the QuotaClient is destructed.
   virtual void DeleteOriginData(const GURL& origin,
                                 StorageType type,
                                 const DeletionCallback& callback) = 0;
+
+  virtual bool DoesSupport(StorageType type) const = 0;
 };
 
 // TODO(dmikurube): Replace it to std::vector for efficiency.
 typedef std::list<QuotaClient*> QuotaClientList;
 
 }  // namespace quota
 
 #endif  // WEBKIT_BROWSER_QUOTA_QUOTA_CLIENT_H_