[PPAPI] Implement an IOStreamResource for data transmission between plugin and renderer.

content/renderer/pepper/pepper_io_stream_host.h

+// Copyright (c) 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_RENDERER_PEPPER_PEPPER_IO_STREAM_HOST_H_
+#define CONTENT_RENDERER_PEPPER_PEPPER_IO_STREAM_HOST_H_
+
+#include "base/compiler_specific.h"
+#include "content/common/content_export.h"
+#include "ppapi/host/host_message_context.h"
+#include "ppapi/host/resource_host.h"
+#include "ppapi/shared_impl/io_stream_shared.h"
+
+namespace content {
+
+class RendererPpapiHost;
+
+class PepperIOStreamHost

[yzshen1, 2014/01/03 21:51:41]

Please consider naming it ...Base.

+    : public ppapi::host::ResourceHost,
+      public ppapi::IOStreamShared {
+ protected:
+  PepperIOStreamHost(RendererPpapiHost* host,
+                     PP_Instance instance,
+                     PP_Resource resource,
+                     bool is_input);
+
+  virtual ~PepperIOStreamHost();
+
+  virtual int32_t OnResourceMessageReceived(
+      const IPC::Message& msg,
+      ppapi::host::HostMessageContext* context) OVERRIDE;
+
+  bool InitSharedBufferAndNotifyPlugin(uint32_t size);
+
+ private:
+  bool InitSharedBuffer(uint32_t size);
+
+  int32_t OnHostMsgInit(ppapi::host::HostMessageContext* context,
+                        uint32_t size);
+
+  int32_t OnHostMsgMoveLimit(ppapi::host::HostMessageContext* context,
+                             uint32_t offset);
+
+  // Overridden from ppapi::IOStreamShared.
+  void MovePeerLimit(uint32_t offset) OVERRIDE;
+
+  DISALLOW_COPY_AND_ASSIGN(PepperIOStreamHost);
+};
+
+}  // namespace content
+
+#endif  // CONTENT_RENDERER_PEPPER_PEPPER_IO_STREAM_HOST_H_