Add a menu option for the right-hand Ctrl -> Meta mapping.

remoting/webapp/base/js/host.js

Index: remoting/webapp/base/js/host.js
diff --git a/remoting/webapp/base/js/host.js b/remoting/webapp/base/js/host.js
index 48b62406e4b36febbbf50d84da469fdf98b5fecf..a7c7e8dcb4898335cb1afaac24def638d07116fb 100644
--- a/remoting/webapp/base/js/host.js
+++ b/remoting/webapp/base/js/host.js
@@ -99,7 +99,7 @@ remoting.Host.Options.prototype.load = function() {
       } else if (typeof(remappings) !== 'object') {
         remappings = {};
       }
-      that.remapKeys = remappings;
+      that.remapKeys = /** @type {!Object} */ (base.deepCopy(remappings));
     });
 };