Implement host settings migration.

remoting/webapp/crd/js/background.js

Index: remoting/webapp/crd/js/background.js
diff --git a/remoting/webapp/crd/js/background.js b/remoting/webapp/crd/js/background.js
index 032593507800459c26ac32ed1304b8f900445eca..ec1f9c2e7b270a71b7f9b47d9fb587b22cf0ae21 100644
--- a/remoting/webapp/crd/js/background.js
+++ b/remoting/webapp/crd/js/background.js
@@ -19,6 +19,8 @@ var BackgroundPage = function() {
   this.activationHandler_ = null;
   /** @private {remoting.TelemetryEventWriter.Service} */
   this.telemetryService_ = null;
+  /** @private {remoting.OptionsExporter} */
+  this.optionsExporter_ = null;
   /** @private */
   this.disposables_ = new base.Disposables();
   this.preInit_();
@@ -49,6 +51,7 @@ BackgroundPage.prototype.preInit_ = function() {
     this.disposables_.add(new base.EventHook(
         this.activationHandler_, remoting.ActivationHandler.Events.windowClosed,
         this.telemetryService_.unbindSession.bind(this.telemetryService_)));
+    this.optionsExporter_ = new remoting.OptionsExporter();
   } else {
     this.appLauncher_ = new remoting.V1AppLauncher();
   }