[Blimp] Adds Blimp EngineSession and ClientSession skeleton

blimp/engine/browser/blimp_client_session_manager_delegate.h

Index: blimp/engine/browser/blimp_client_session_manager_delegate.h
diff --git a/blimp/engine/browser/blimp_client_session_manager_delegate.h b/blimp/engine/browser/blimp_client_session_manager_delegate.h
new file mode 100644
index 0000000000000000000000000000000000000000..9040d9a3f46528729bde8a74779d51c4127a14ae
--- /dev/null
+++ b/blimp/engine/browser/blimp_client_session_manager_delegate.h
@@ -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.
+
+#ifndef BLIMP_ENGINE_BROWSER_BLIMP_CLIENT_SESSION_MANAGER_DELEGATE_H_
+#define BLIMP_ENGINE_BROWSER_BLIMP_CLIENT_SESSION_MANAGER_DELEGATE_H_
+
+#include "blimp/engine/browser/blimp_client_session.h"
+
+namespace blimp {
+namespace engine {
+
+class BlimpClientSessionManagerDelegate {
+ public:
+  virtual ~BlimpClientSessionManagerDelegate() {}
+
+  // Attaches a new client session to the engine. There must not be an
+  // existing attached client session.
+  // Caller owns |client_session|.
+  virtual void AttachClientSession(BlimpClientSession* client_session) = 0;

[Kevin M, 2015/10/14 17:52:57]

I recommend rephrasing these to "ClientSessionCreated" and
"ClientSessionDestroyed".

It's up to the delegate subclass to decide what to do with that session
(attach/detach).

[haibinlu, 2015/10/15 01:59:28]

per offline discussion, rename this class to 'handler' and keep the method name.

+
+  // Detaches an existing client session from the engine.
+  virtual void DetachClientSession(BlimpClientSession* client_session) = 0;
+};
+
+}  // namespace engine
+}  // namespace blimp
+
+#endif  // BLIMP_ENGINE_BROWSER_BLIMP_CLIENT_SESSION_MANAGER_DELEGATE_H_