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

remoting/proto/event.proto

 // Copyright (c) 2012 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.
 
 // Protocol for event messages.
 
 syntax = "proto2";
 
 option optimize_for = LITE_RUNTIME;
 
@@ skipping 30 matching lines @@
   // These values encode the number of wheel 'ticks' (sometimes called
   // 'clicks' although 'ticks' is the most common cross-platform term).
   // Additional fields may be added later to support high-resolution devices.
   optional int32 wheel_offset_x = 3;
   optional int32 wheel_offset_y = 4;
 
   // Mouse button event.
   optional MouseButton button = 5;
   optional bool button_down = 6;
 }
+
+// Defines an event that sends clipboard data between peers.
+message ClipboardEvent {
+
+  // The MIME type of the data being sent.
+  optional string mime_type = 1;
+
+  // The data being sent.
+  optional bytes data = 2;
+}