Add interfaces for most major Blimp net components.

blimp/net/blimp_message_demultiplexer.h

Index: blimp/net/blimp_message_demultiplexer.h
diff --git a/blimp/net/blimp_message_demultiplexer.h b/blimp/net/blimp_message_demultiplexer.h
new file mode 100644
index 0000000000000000000000000000000000000000..6ec7bc93232dd82fc028895d7b544ba0bfa39ee9
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+++ b/blimp/net/blimp_message_demultiplexer.h
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+// 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 BLIMP_NET_BLIMP_MESSAGE_DEMULTIPLEXER_H_
+#define BLIMP_NET_BLIMP_MESSAGE_DEMULTIPLEXER_H_
+
+#include <map>
+
+#include "base/containers/small_map.h"
+#include "base/macros.h"
+#include "base/threading/thread_checker.h"
+#include "blimp/common/proto/blimp_message.pb.h"
+#include "blimp/net/blimp_message_processor.h"
+#include "blimp/net/blimp_net_export.h"
+
+namespace blimp {
+
+// Multiplexing BlimpMessageProcessor which routes BlimpMessages to message
+// processors based on |message.type|.
+class BLIMP_NET_EXPORT BlimpMessageDemultiplexer
+    : public BlimpMessageProcessor {
+ public:
+  BlimpMessageDemultiplexer();
+  ~BlimpMessageDemultiplexer() override;
+
+  // Registers a message processor which will receive all messages
+  // of the |type| specified.
+  // Only one handler may be added per type.
+  //
+  // |handler| must be valid when ProcessMessage() is called.
+  void AddProcessor(BlimpMessage::Type type, BlimpMessageProcessor* handler);
+
+  // BlimpMessageProcessor implementation.
+  void ProcessMessage(const BlimpMessage& message,
+                      const net::CompletionCallback& callback) override;
+
+ private:
+  base::SmallMap<std::map<BlimpMessage::Type, BlimpMessageProcessor*>>
+      feature_receiver_map_;
+
+  DISALLOW_COPY_AND_ASSIGN(BlimpMessageDemultiplexer);
+};
+
+}  // namespace blimp
+
+#endif  // BLIMP_NET_BLIMP_MESSAGE_DEMULTIPLEXER_H_