[Chromoting] Add plumbing to carry clipboard events from the host to the client.

remoting/protocol/host_control_dispatcher.cc

Index: remoting/protocol/host_control_dispatcher.cc
diff --git a/remoting/protocol/host_control_dispatcher.cc b/remoting/protocol/host_control_dispatcher.cc
index 2dc436426cdb24a14cc891c3d9994aa768d52f6f..4a78d0e21ecf24a474cac9cfe4eb12d294cbc16d 100644
--- a/remoting/protocol/host_control_dispatcher.cc
+++ b/remoting/protocol/host_control_dispatcher.cc
@@ -34,6 +34,12 @@ void HostControlDispatcher::OnInitialized() {
   writer_->Init(channel(), BufferedSocketWriter::WriteFailedCallback());
 }
 
+void HostControlDispatcher::InjectClipboardEvent(const ClipboardEvent& event) {
+  ControlMessage message;
+  message.mutable_clipboard_event()->CopyFrom(event);
+  writer_->Write(SerializeAndFrameMessage(message), base::Closure());
+}
+
 void HostControlDispatcher::OnMessageReceived(
     scoped_ptr<ControlMessage> message, const base::Closure& done_task) {
   DCHECK(clipboard_stub_);