Add an injectKeyEvent API to the Chromoting client plugin.

remoting/webapp/client_plugin.js

Index: remoting/webapp/client_plugin.js
diff --git a/remoting/webapp/client_plugin.js b/remoting/webapp/client_plugin.js
index 336e17e93058f156d13d00f97286ad531440ee0f..2ed61069b2ebdf84944071c5731514e7495fe268 100644
--- a/remoting/webapp/client_plugin.js
+++ b/remoting/webapp/client_plugin.js
@@ -91,6 +91,14 @@ remoting.ClientPlugin.prototype.setScaleToFit =
 remoting.ClientPlugin.prototype.releaseAllKeys = function() {};
 
 /**
+ * Send a key event to the host.
+ *
+ * @param {number} usb_keycode The USB-style code of the key to inject.
+ * @param {boolean} pressed True to inject a key press, False for a release.
+ */
+remoting.ClientPlugin.prototype.injectKey = function() {};
+
+/**
  * Returns an associative array with a set of stats for this connection.
  *
  * @return {remoting.ClientSession.PerfStats} The connection statistics.