Add the plumbing that will carry a clipboard item from a chromoting client to a host.

remoting/host/client_session.h

Index: remoting/host/client_session.h
diff --git a/remoting/host/client_session.h b/remoting/host/client_session.h
index 31ac0793dcf81b0cabad117c7bb91d8a37800aa5..72c283eb224274b994f72f21a47832b0b3e7cbe1 100644
--- a/remoting/host/client_session.h
+++ b/remoting/host/client_session.h
@@ -10,6 +10,7 @@
 
 #include "base/time.h"
 #include "base/threading/non_thread_safe.h"
+#include "remoting/protocol/clipboard_stub.h"
 #include "remoting/protocol/connection_to_client.h"
 #include "remoting/protocol/host_stub.h"
 #include "remoting/protocol/input_stub.h"
@@ -21,7 +22,8 @@ class Capturer;
 
 // A ClientSession keeps a reference to a connection to a client, and maintains
 // per-client state.
-class ClientSession : public protocol::HostStub,
+class ClientSession : public protocol::ClipboardStub,
+                      public protocol::HostStub,
                       public protocol::InputStub,
                       public protocol::ConnectionToClient::EventHandler,
                       public base::NonThreadSafe {
@@ -57,13 +59,18 @@ class ClientSession : public protocol::HostStub,
   };
 
   // Takes ownership of |connection|. Does not take ownership of
-  // |event_handler|, |input_stub| or |capturer|.
+  // |event_handler|, |clipboard_stub|, |input_stub| or |capturer|.
   ClientSession(EventHandler* event_handler,
                 protocol::ConnectionToClient* connection,
+                protocol::ClipboardStub* clipboard_stub,
                 protocol::InputStub* input_stub,
                 Capturer* capturer);
   virtual ~ClientSession();
 
+  // protocol::ClipboardStub interface.
+  virtual void InjectClipboardEvent(
+      const protocol::ClipboardEvent& event) OVERRIDE;
+
   // protocol::InputStub interface.
   virtual void InjectKeyEvent(const protocol::KeyEvent& event) OVERRIDE;
   virtual void InjectMouseEvent(const protocol::MouseEvent& event) OVERRIDE;
@@ -130,6 +137,9 @@ class ClientSession : public protocol::HostStub,
 
   std::string client_jid_;
 
+  // The clipboard stub to which this object delegates.
+  protocol::ClipboardStub* clipboard_stub_;
+
   // The input stub to which this object delegates.
   protocol::InputStub* input_stub_;