Allow script to request durable storage permission (chrome side)

storage/browser/quota/special_storage_policy.h

Index: storage/browser/quota/special_storage_policy.h
diff --git a/storage/browser/quota/special_storage_policy.h b/storage/browser/quota/special_storage_policy.h
index d164e94281229c3ef7568d1d875f16a821903c83..5c865e2d308992ebe3581c8153f2c7ac02c58de1 100644
--- a/storage/browser/quota/special_storage_policy.h
+++ b/storage/browser/quota/special_storage_policy.h
@@ -62,6 +62,8 @@ class STORAGE_EXPORT SpecialStoragePolicy
   // Returns true if some origins are only allowed session-only storage.
   virtual bool HasSessionOnlyOrigins() = 0;
 
+  virtual bool IsStorageDurable(const GURL& origin) = 0;
+
   // Adds/removes an observer, the policy does not take
   // ownership of the observer. Should only be called on the IO thread.
   void AddObserver(Observer* observer);