Introduce StreamRegistry::NotifyReaderAbortedBeforeRegistration()

content/browser/streams/stream_registry.h

 // Copyright (c) 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 CONTENT_BROWSER_STREAMS_STREAM_REGISTRY_H_
 #define CONTENT_BROWSER_STREAMS_STREAM_REGISTRY_H_
 
 #include <map>
+#include <set>
 
 #include "base/basictypes.h"
 #include "base/memory/ref_counted.h"
 #include "base/threading/non_thread_safe.h"
 #include "content/browser/streams/stream_register_observer.h"
 #include "content/common/content_export.h"
 #include "url/gurl.h"
 
 namespace content {
 
 class Stream;
 
 // Maintains a mapping of blob: URLs to active streams.
 class CONTENT_EXPORT StreamRegistry : public base::NonThreadSafe {
  public:
   StreamRegistry();
   virtual ~StreamRegistry();
 
   // Registers a stream, and sets its URL.
-  void RegisterStream(scoped_refptr<Stream> stream);
+  void RegisterStream(Stream* stream);
 
   // Clones a stream.  Returns true on success, or false if |src_url| doesn't
   // exist.
   bool CloneStream(const GURL& url, const GURL& src_url);
 
   void UnregisterStream(const GURL& url);
 
   // Called by Stream instances to request increase of memory usage. If the
   // total memory usage for this registry is going to exceed the limit,
   // returns false. Otherwise, updates |total_memory_usage_| and returns true.
   //
   // |current_size| is the up-to-date size of ByteStream of the Stream instance
   // and |increase| must be the amount of data going to be added to the Stream
   // instance.
   bool UpdateMemoryUsage(const GURL& url, size_t current_size, size_t increase);
 
   // Gets the stream associated with |url|.  Returns NULL if there is no such
   // stream.
   scoped_refptr<Stream> GetStream(const GURL& url);
 
   void set_max_memory_usage_for_testing(size_t size) {
     max_memory_usage_ = size;
   }
 
   void SetRegisterObserver(const GURL& url, StreamRegisterObserver* observer);
   void RemoveRegisterObserver(const GURL& url);
 
+  // If the reader is aborted before the stream is registered, call this method
+  // to reduce the memory consumption. After this method is called,
+  // RegisterStream doesn't register the stream of the URL.
+  void AbortPendingStream(const GURL& url);
+
  private:
   typedef std::map<GURL, scoped_refptr<Stream> > StreamMap;
 
   StreamMap streams_;
   std::map<GURL, StreamRegisterObserver*> register_observers_;
+  std::set<GURL> reader_aborted_urls_;
 
   size_t total_memory_usage_;
 
   // Maximum amount of memory allowed to use for Stream instances registered
   // with this registry.
   size_t max_memory_usage_;
 
   DISALLOW_COPY_AND_ASSIGN(StreamRegistry);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_BROWSER_STREAMS_STREAM_REGISTRY_H_