[AppRemoting] Break out AppRemoting shared module (re-land).

remoting/webapp/crd/js/desktop_remoting.js

Index: remoting/webapp/crd/js/desktop_remoting.js
diff --git a/remoting/webapp/crd/js/desktop_remoting.js b/remoting/webapp/crd/js/desktop_remoting.js
index 965dc939c9af5d49e5d5a2cd0a42bb54d80379a9..09bb38e30e172745a589cdb4796fe8309bea47e0 100644
--- a/remoting/webapp/crd/js/desktop_remoting.js
+++ b/remoting/webapp/crd/js/desktop_remoting.js
@@ -48,6 +48,15 @@ remoting.DesktopRemoting.prototype.getConnectionMode = function() {
 };
 
 /**
+ * @return {string} Application Id.
+ * @override {remoting.ApplicationInterface}
+ */
+remoting.DesktopRemoting.prototype.getApplicationId = function() {
+  // Application IDs are not used in desktop remoting.
+  return '';
+};
+
+/**
  * @return {string} Application product name to be used in UI.
  * @override {remoting.ApplicationInterface}
  */