Implement WebDataConsumerHandle::Reader.

content/child/shared_memory_data_consumer_handle.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_CHILD_SHARED_MEMORY_DATA_CONSUMER_HANDLE_H_
 #define CONTENT_CHILD_SHARED_MEMORY_DATA_CONSUMER_HANDLE_H_
 
 #include "base/memory/ref_counted.h"
 #include "base/memory/scoped_ptr.h"
 #include "content/common/content_export.h"
@@ skipping 21 matching lines @@
     void AddData(scoped_ptr<RequestPeer::ReceivedData> data);
     void Close();
 
    private:
     scoped_refptr<Context> context_;
     BackpressureMode mode_;
 
     DISALLOW_COPY_AND_ASSIGN(Writer);
   };
 
+  class ReaderImpl final : public Reader {
+   public:
+    ReaderImpl(scoped_refptr<Context> context, Client* client);
+    virtual ~ReaderImpl();
+    virtual Result read(void* data, size_t size, Flags flags, size_t* readSize);
+    virtual Result beginRead(const void** buffer,
+                             Flags flags,
+                             size_t* available);
+    virtual Result endRead(size_t readSize);
+
+   private:
+    scoped_refptr<Context> context_;
+
+    DISALLOW_COPY_AND_ASSIGN(ReaderImpl);
+ };
+
   SharedMemoryDataConsumerHandle(BackpressureMode mode,
                                  scoped_ptr<Writer>* writer);
   virtual ~SharedMemoryDataConsumerHandle();
 
+  scoped_ptr<Reader> ObtainReader(Client* client);
+
   virtual Result read(void* data, size_t size, Flags flags, size_t* readSize);
   virtual Result beginRead(const void** buffer, Flags flags, size_t* available);
   virtual Result endRead(size_t readSize);
   virtual void registerClient(Client* client);
   virtual void unregisterClient();
 
  private:
+  virtual ReaderImpl* obtainReaderInternal(Client* client);
+  void LockImplicitly();
+  void UnlockImplicitly();
+
   scoped_refptr<Context> context_;
+  // This is an implicitly acquired reader for deprecated APIs.
+  scoped_ptr<Reader> reader_;
 
   DISALLOW_COPY_AND_ASSIGN(SharedMemoryDataConsumerHandle);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_CHILD_SHARED_MEMORY_DATA_CONSUMER_HANDLE_H_