Release all keys on blur.

remoting/webapp/me2mom/remoting.js

 // Copyright (c) 2011 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.
 
 var remoting = remoting || {};
 
 (function() {
 "use strict";
 
+window.addEventListener('blur', pluginLostFocus_, false);
+
+function pluginLostFocus_() {
+  // If the plug loses input focus, release all keys as a precaution against
+  // leaving them 'stuck down' on the host.
+  if (remoting.session && remoting.session.plugin) {
+    remoting.session.plugin.releaseAllKeys();
+  }
+}
+
 /** @enum {string} */
 remoting.AppMode = {
   CLIENT: 'client',
   HOST: 'host',
   IN_SESSION: 'in-session'
 };
 
 remoting.EMAIL = 'email';
 remoting.HOST_PLUGIN_ID = 'host-plugin-id';
 
@@ skipping 488 matching lines @@
 }
 
 remoting.toggleScaleToFit = function() {
   remoting.scaleToFit = !remoting.scaleToFit;
   document.getElementById('scale-to-fit-toggle').value =
       remoting.scaleToFit ? 'No scaling' : 'Scale to fit';
   remoting.session.toggleScaleToFit(remoting.scaleToFit);
 }
 
 }());