Add interfaces for most major Blimp net components.

blimp/engine/net/engine_connection_manager.cc

Index: blimp/engine/net/engine_connection_manager.cc
diff --git a/blimp/engine/net/engine_connection_manager.cc b/blimp/engine/net/engine_connection_manager.cc
new file mode 100644
index 0000000000000000000000000000000000000000..390ff4ce87aa52151d7ec05a36316a01452e3151
--- /dev/null
+++ b/blimp/engine/net/engine_connection_manager.cc
@@ -0,0 +1,29 @@
+// 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.
+
+#include "blimp/engine/net/engine_connection_manager.h"
+
+#include "base/logging.h"
+
+namespace blimp {
+
+EngineConnectionManager::EngineConnectionManager(
+    ConnectionHandler* engine_browser_session) {
+  NOTIMPLEMENTED();
+}
+
+void EngineConnectionManager::StartListening() {
+  NOTIMPLEMENTED();
+}
+
+void EngineConnectionManager::HandleConnection(
+    scoped_ptr<BlimpConnection> connection) {
+  NOTIMPLEMENTED();
+}
+
+void EngineConnectionManager::OnDisconnected() {
+  NOTIMPLEMENTED();
+}
+
+}  // namespace blimp