Only set size and load URL on first attach

lib/browser/guest-view-manager.js

@@ -78,7 +78,15 @@ const createGuest = function (embedder, params) {
   guest.on('did-attach', function () {
     params = this.attachParams
     delete this.attachParams
+
+    const previouslyAttached = this.viewInstanceId != null
     this.viewInstanceId = params.instanceId
+
+    // Only load URL and set size on first attach
+    if (previouslyAttached) {
+      return
+    }
+
     this.setSize({
       normal: {
         width: params.elementWidth,