Add interfaces for most major Blimp net components.

blimp/net/blimp_message_output_buffer.h

Index: blimp/net/blimp_message_output_buffer.h
diff --git a/blimp/net/blimp_message_output_buffer.h b/blimp/net/blimp_message_output_buffer.h
new file mode 100644
index 0000000000000000000000000000000000000000..03c9beb9e345f55b62b5fa9d1a7fb0f34bc06561
--- /dev/null
+++ b/blimp/net/blimp_message_output_buffer.h
@@ -0,0 +1,53 @@
+// 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_OUTPUT_BUFFER_H_
+#define BLIMP_NET_BLIMP_MESSAGE_OUTPUT_BUFFER_H_
+
+#include "base/macros.h"
+#include "blimp/net/blimp_message_checkpoint_observer.h"
+#include "blimp/net/blimp_message_processor.h"
+#include "blimp/net/blimp_net_export.h"
+
+namespace blimp {
+
+class BlimpConnection;
+
+// Provides a FIFO buffer for reliable, ordered message delivery.
+// Messages are retained for redelivery until they are acknowledged by the
+// receiving end (via BlimpMessageAckObserver).
+// (Redelivery will be used in a future CL to implement Fast Recovery
+// of dropped connections.)
+class BLIMP_NET_EXPORT BlimpMessageOutputBuffer
+    : public BlimpMessageProcessor,
+      public BlimpMessageCheckpointObserver {
+ public:
+  BlimpMessageOutputBuffer();
+  ~BlimpMessageOutputBuffer() override;
+
+  // Sets the processor to receive messages from this buffer.
+  void set_outgoing_message_processor(BlimpMessageProcessor* processor) {
+    NOTIMPLEMENTED();

[Wez, 2015/11/12 03:45:57]

Simple setter is no good if it's not simple. Let's make this a comment for now?

[Kevin M, 2015/11/12 19:03:47]

Done.

+  }
+
+  // BlimpMessageProcessor implementation.
+  // |callback|, if set, will be called once the remote end has acknowledged the
+  // receipt of |message|.
+  void ProcessMessage(const BlimpMessage& message,
+                      const net::CompletionCallback& callback) override;
+
+  // MessageCheckpointObserver implementation.
+  // Flushes acknowledged messages from the buffer and invokes their
+  // |callbacks|, if any.
+  // Callbacks should not destroy |this| so as to not interfere with the
+  // processing of any other pending callbacks.
+  void OnMessageCheckpoint(int64 message_id) override;
+
+ private:
+  DISALLOW_COPY_AND_ASSIGN(BlimpMessageOutputBuffer);
+};
+
+}  // namespace blimp
+
+#endif  // BLIMP_NET_BLIMP_MESSAGE_OUTPUT_BUFFER_H_