Implement WebDataConsumerHandle::Reader.

content/child/web_data_consumer_handle_impl.h

 // Copyright 2014 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_WEB_DATA_CONSUMER_HANDLE_IMPL_H_
 #define CONTENT_CHILD_WEB_DATA_CONSUMER_HANDLE_IMPL_H_
 
 #include "base/memory/scoped_ptr.h"
 #include "content/common/content_export.h"
 #include "mojo/common/handle_watcher.h"
 #include "third_party/WebKit/public/platform/WebDataConsumerHandle.h"
 #include "third_party/mojo/src/mojo/public/cpp/system/data_pipe.h"
 
 namespace content {
 
 class CONTENT_EXPORT WebDataConsumerHandleImpl final
     : public NON_EXPORTED_BASE(blink::WebDataConsumerHandle) {
   typedef mojo::ScopedDataPipeConsumerHandle Handle;
+  class Context;
+
  public:
+  class CONTENT_EXPORT ReaderImpl final : public NON_EXPORTED_BASE(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:
+    Result HandleReadResult(MojoResult);
+    void StartWatching();
+    void OnHandleGotReadable(MojoResult);
+
+    scoped_refptr<Context> context_;
+    mojo::common::HandleWatcher handle_watcher_;
+    Client* client_;
+  };
+  scoped_ptr<Reader> ObtainReader(Client* client);
+
   explicit WebDataConsumerHandleImpl(Handle handle);
   virtual ~WebDataConsumerHandleImpl();
 
-  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);
 
- private:
-  Result HandleReadResult(MojoResult);
-  void OnHandleGotReadable(MojoResult);
-
-  Handle handle_;
-  Client* client_;
-  mojo::common::HandleWatcher handle_watcher_;
+  scoped_refptr<Context> context_;
 };
 
 }  // namespace content
 
 #endif  // CONTENT_CHILD_WEB_DATA_CONSUMER_HANDLE_IMPL_H_