Move needsPreviewElement to TimelineUIUtilsImple and make it private

Source/devtools/front_end/timeline/TimelineUIUtilsImpl.js

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 /**
  * @constructor
  * @extends {WebInspector.TimelineUIUtils}
  */
 WebInspector.TimelineUIUtilsImpl = function()
 {
@@ skipping 248 matching lines @@
     {
         if (record.stackTrace())
             return linkifyCallFrame(record.stackTrace()[0]);
         if (record.callSiteStackTrace())
             return linkifyCallFrame(record.callSiteStackTrace()[0]);
         return null;
     }
 }
 
 /**
+ * @param {string=} recordType
+ * @return {boolean}
+ */
+WebInspector.TimelineUIUtilsImpl._needsPreviewElement = function(recordType)
+{
+    if (!recordType)
+        return false;
+    const recordTypes = WebInspector.TimelineModel.RecordType;
+    switch (recordType) {
+    case recordTypes.ResourceSendRequest:
+    case recordTypes.ResourceReceiveResponse:
+    case recordTypes.ResourceReceivedData:
+    case recordTypes.ResourceFinish:
+        return true;
+    default:
+        return false;
+    }
+}
+
+/**
  * @param {!WebInspector.TimelineModel.Record} record
  * @param {!WebInspector.TimelineModel} model
  * @param {!WebInspector.Linkifier} linkifier
  * @param {function(!DocumentFragment)} callback
  * @param {boolean} loadedFromFile
  */
 WebInspector.TimelineUIUtilsImpl.generateDetailsContent = function(record, model, linkifier, callback, loadedFromFile)
 {
     var imageElement = /** @type {?Element} */ (record.getUserObject("TimelineUIUtils::preview-element") || null);
     var relatedNode = null;
     var recordData = record.data();
     var barrier = new CallbackBarrier();
-    if (!imageElement && WebInspector.TimelineUIUtils.needsPreviewElement(record.type()))
+    if (!imageElement && WebInspector.TimelineUIUtilsImpl._needsPreviewElement(record.type()))
         WebInspector.DOMPresentationUtils.buildImagePreviewContents(record.target(), recordData["url"], false, barrier.createCallback(saveImage));
     if (recordData["backendNodeId"])
         record.target().domModel.pushNodesByBackendIdsToFrontend([recordData["backendNodeId"]], barrier.createCallback(setRelatedNode));
     barrier.callWhenDone(callbackWrapper);
 
     /**
      * @param {!Element=} element
      */
     function saveImage(element)
     {
@@ skipping 201 matching lines @@
     else if (recordType === recordTypes.TimeStamp)
         eventDivider.className += " resources-orange-divider";
     else if (recordType === recordTypes.BeginFrame)
         eventDivider.className += " timeline-frame-divider";
 
     if (title)
         eventDivider.title = title;
 
     return eventDivider;
 }