defer loading visualization saved objects so they can be loaded in a single _mget

src/core_plugins/kibana/public/dashboard/panel/load_saved_object.js

@@ -10,6 +10,7 @@ export function loadSavedObject(loaders, panel) {
   if (!loader) {
     throw new Error(`No loader for object of type ${panel.type}`);
   }
-  return loader.get(panel.id)
+  const isDefered = true;
+  return loader.get(panel.id, isDefered)
     .then(savedObj => ({ savedObj, editUrl: loader.urlFor(panel.id) }));
 }

src/ui/public/courier/saved_object/saved_object.js

@@ -127,7 +127,7 @@ export default function SavedObjectFactory(esAdmin, kbnIndex, Promise, Private,
      * @return {Promise}
      * @resolved {SavedObject}
      */
-    this.init = _.once(() => {
+    this.init = _.once((isDefered) => {
       // ensure that the type is defined
       if (!type) throw new Error('You must define a type name to use SavedObject objects.');
 
@@ -166,7 +166,13 @@ export default function SavedObjectFactory(esAdmin, kbnIndex, Promise, Private,
           }
 
           // fetch the object from ES
-          return docSource.fetch().then(this.applyESResp);
+          if (isDefered) {
+            const defer = Promise.defer();
+            docSource._createRequest(defer);
+            return defer.promise.then(this.applyESResp);
+          } else {
+            return docSource.fetch().then(this.applyESResp);
+          }
         })
         .then(() => {
           return customInit.call(this);

src/ui/public/courier/saved_object/saved_object_loader.js

@@ -29,8 +29,8 @@ export class SavedObjectLoader {
    * @param id
    * @returns {Promise<SavedObject>}
    */
-  get(id) {
-    return (new this.Class(id)).init();
+  get(id, isDefered) {
+    return (new this.Class(id)).init(isDefered);
   }
 
   urlFor(id) {