Make SharedMemoryDataConsumerHandle thread-safe.

content/public/child/fixed_received_data.h

 // Copyright 2015 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_PUBLIC_CHILD_FIXED_RECEIVED_DATA_H_
 #define CONTENT_PUBLIC_CHILD_FIXED_RECEIVED_DATA_H_
 
 #include <vector>
 
 #include "content/common/content_export.h"
 #include "content/public/child/request_peer.h"
 
 namespace content {
 
 class CONTENT_EXPORT FixedReceivedData final
-    : public RequestPeer::ReceivedData {
+    : public RequestPeer::ThreadSafeReceivedData {
  public:
   FixedReceivedData(const char* data, size_t length, int encoded_length);
   explicit FixedReceivedData(ReceivedData* data);
   FixedReceivedData(const std::vector<char>& data, int encoded_length);
   ~FixedReceivedData() override;
 
   const char* payload() const override;
   int length() const override;
   int encoded_length() const override;
 
  private:
   std::vector<char> data_;
   int encoded_length_;
 
   DISALLOW_COPY_AND_ASSIGN(FixedReceivedData);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_PUBLIC_CHILD_FIXED_RECEIVED_DATA_H_