[Webapp Refactor] Move key injection logic into the plugin layer.

remoting/webapp/crd/js/client_plugin.js

Index: remoting/webapp/crd/js/client_plugin.js
diff --git a/remoting/webapp/crd/js/client_plugin.js b/remoting/webapp/crd/js/client_plugin.js
index 66b9fd3b3a279ec6eb1625a55e2a4e0c3ad9be98..325117f51713e10483b74356dfe00193b631dc1a 100644
--- a/remoting/webapp/crd/js/client_plugin.js
+++ b/remoting/webapp/crd/js/client_plugin.js
@@ -49,6 +49,22 @@ remoting.ClientPlugin.prototype.injectKeyEvent =
     function(key, down) {};
 
 /**
+ * Sends a key combination to the host, by sending down events for
+ * the given keys, followed by up events in reverse order.
+ *
+ * @param {Array<number>} keys Key codes to be sent.
+ * @return {void} Nothing.
+ */
+remoting.ClientPlugin.prototype.injectKeyCombination = function(keys) {};
+
+/**
+ * Sets and stores the key remapping setting for the current host.
+ *
+ * @param {string} remappings Comma separated list of key remappings.
+ */
+remoting.ClientPlugin.prototype.setRemapKeys = function(remappings) {};
+
+/**
  * @param {number} from
  * @param {number} to
  */