[Cronet] Use WeakPtr in CronetBidirectionalStream on iOS.

components/cronet/ios/cronet_bidirectional_stream.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 COMPONENTS_CRONET_IOS_CRONET_BIDIRECTIONAL_STREAM_H_
 #define COMPONENTS_CRONET_IOS_CRONET_BIDIRECTIONAL_STREAM_H_
 
 #include <memory>
 #include <vector>
 
 #include "base/macros.h"
 #include "base/memory/ref_counted.h"
+#include "base/memory/weak_ptr.h"
 #include "base/synchronization/lock.h"
 #include "net/http/bidirectional_stream.h"
 
 namespace net {
 class HttpRequestHeaders;
 class WrappedIOBuffer;
 }  // namespace net
 
 namespace cronet {
 
@@ skipping 190 matching lines @@
   // Write data that is pending the flush.
   std::unique_ptr<WriteBuffers> pending_write_data_;
   // Write data that is flushed, but not sending yet.
   std::unique_ptr<WriteBuffers> flushing_write_data_;
   // Write data that is sending.
   std::unique_ptr<WriteBuffers> sending_write_data_;
 
   std::unique_ptr<net::BidirectionalStream> bidi_stream_;
   Delegate* delegate_;
 
+  base::WeakPtr<CronetBidirectionalStream> weak_this_;
+  base::WeakPtrFactory<CronetBidirectionalStream> weak_factory_;
+
   DISALLOW_COPY_AND_ASSIGN(CronetBidirectionalStream);
 };
 
 }  // namespace cronet
 
 #endif  // COMPONENTS_CRONET_IOS_CRONET_BIDIRECTIONAL_STREAM_H_