Optionally have MessagePort pass data as base::Value, part 1.

content/public/common/message_port_types.h

Index: content/public/common/message_port_types.h
diff --git a/content/public/common/message_port_types.h b/content/public/common/message_port_types.h
new file mode 100644
index 0000000000000000000000000000000000000000..961afe22a5e8d3fad5d4b063c69a3d6fca6bb446
--- /dev/null
+++ b/content/public/common/message_port_types.h
@@ -0,0 +1,42 @@
+// 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_COMMON_MESSAGE_PORT_TYPES_H_
+#define CONTENT_PUBLIC_COMMON_MESSAGE_PORT_TYPES_H_
+
+#include <vector>
+
+#include "base/memory/scoped_ptr.h"
+#include "base/strings/string16.h"
+#include "base/values.h"
+#include "content/common/content_export.h"
+
+namespace content {
+
+// Struct representing a message sent across a message port. This struct hides
+// the fact that messages can be serialized/encoded in multiple ways from code
+// that doesn't care about the message contents.
+struct CONTENT_EXPORT MessagePortMessage {
+  MessagePortMessage();
+  explicit MessagePortMessage(const base::string16& message);
+  explicit MessagePortMessage(scoped_ptr<base::Value> message);
+  MessagePortMessage(const MessagePortMessage& other);
+  MessagePortMessage& operator=(const MessagePortMessage& other);
+  ~MessagePortMessage();
+
+  bool is_string() const { return !message_as_string.empty(); }
+  bool is_value() const { return !message_as_value.empty(); }
+  const base::Value* as_value() const;
+
+  // Message serialized using blink::WebSerializedScriptValue. Only one of
+  // |message_as_string| and |message_as_value| should be non-empty.
+  base::string16 message_as_string;
+  // Message as a base::Value. This is either an empty list or a list
+  // containing exactly one item.
+  base::ListValue message_as_value;
+};
+
+}  // namespace content
+
+#endif  // CONTENT_PUBLIC_COMMON_MESSAGE_PORT_TYPES_H_